diff --git a/Cargo.lock b/Cargo.lock
index 3641f73..3b62c5c 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -80,12 +80,102 @@ name = "distributed-systems-flyio"
 version = "0.1.0"
 dependencies = [
  "dashmap",
+ "futures",
  "rand",
  "serde",
  "serde_json",
  "tokio",
 ]
 
+[[package]]
+name = "futures"
+version = "0.3.30"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "645c6916888f6cb6350d2550b80fb63e734897a8498abe35cfb732b6487804b0"
+dependencies = [
+ "futures-channel",
+ "futures-core",
+ "futures-executor",
+ "futures-io",
+ "futures-sink",
+ "futures-task",
+ "futures-util",
+]
+
+[[package]]
+name = "futures-channel"
+version = "0.3.30"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "eac8f7d7865dcb88bd4373ab671c8cf4508703796caa2b1985a9ca867b3fcb78"
+dependencies = [
+ "futures-core",
+ "futures-sink",
+]
+
+[[package]]
+name = "futures-core"
+version = "0.3.30"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dfc6580bb841c5a68e9ef15c77ccc837b40a7504914d52e47b8b0e9bbda25a1d"
+
+[[package]]
+name = "futures-executor"
+version = "0.3.30"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a576fc72ae164fca6b9db127eaa9a9dda0d61316034f33a0a0d4eda41f02b01d"
+dependencies = [
+ "futures-core",
+ "futures-task",
+ "futures-util",
+]
+
+[[package]]
+name = "futures-io"
+version = "0.3.30"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a44623e20b9681a318efdd71c299b6b222ed6f231972bfe2f224ebad6311f0c1"
+
+[[package]]
+name = "futures-macro"
+version = "0.3.30"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "87750cf4b7a4c0625b1529e4c543c2182106e4dedc60a2a6455e00d212c489ac"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "futures-sink"
+version = "0.3.30"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9fb8e00e87438d937621c1c6269e53f536c14d3fbd6a042bb24879e57d474fb5"
+
+[[package]]
+name = "futures-task"
+version = "0.3.30"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "38d84fa142264698cdce1a9f9172cf383a0c82de1bddcf3092901442c4097004"
+
+[[package]]
+name = "futures-util"
+version = "0.3.30"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3d6401deb83407ab3da39eba7e33987a73c3df0c82b4bb5813ee871c19c41d48"
+dependencies = [
+ "futures-channel",
+ "futures-core",
+ "futures-io",
+ "futures-macro",
+ "futures-sink",
+ "futures-task",
+ "memchr",
+ "pin-project-lite",
+ "pin-utils",
+ "slab",
+]
+
 [[package]]
 name = "getrandom"
 version = "0.2.11"
@@ -217,6 +307,12 @@ version = "0.2.14"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "bda66fc9667c18cb2758a2ac84d1167245054bcf85d5d1aaa6923f45801bdd02"
 
+[[package]]
+name = "pin-utils"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8b870d8c151b6f2fb93e84a13146138f05d02ed11c7e7c54f8826aaaf7c9f184"
+
 [[package]]
 name = "ppv-lite86"
 version = "0.2.17"
@@ -338,6 +434,15 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "slab"
+version = "0.4.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8f92a496fb766b417c996b9c5e57daf2f7ad3b0bebe1ccfca4856390e3d3bb67"
+dependencies = [
+ "autocfg",
+]
+
 [[package]]
 name = "smallvec"
 version = "1.13.2"
diff --git a/Cargo.toml b/Cargo.toml
index a6d8872..06fbc42 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -7,6 +7,7 @@ edition = "2021"
 
 [dependencies]
 dashmap = "5.5.3"
+futures = "0.3.30"
 rand = { version = "0.8.5", features = ["small_rng"] }
 serde = { version = "1.0.193", features = ["serde_derive"] }
 serde_json = "1.0.109"
diff --git a/src/lib.rs b/src/lib.rs
index 2ba28aa..1e3bbc5 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -2,59 +2,73 @@
 #![feature(hash_set_entry)]
 #![feature(trait_alias)]
 
-pub mod seq_kv;
 pub mod types;
 
-use crate::{seq_kv::MonotonicCounter, types::Message};
-use rand::{rngs::SmallRng, Rng, SeedableRng};
+use crate::types::{Message, MessageBody, SeqKvInput};
+use futures::future::BoxFuture;
+use rand::{rngs::SmallRng, SeedableRng};
 use serde_json::Value;
 use std::{
     collections::HashMap,
-    io::{stdin, stdout, BufRead, Error as IoError, Stdin, Stdout, Write},
+    future::Future,
+    io::{stdin, stdout, BufRead, Error as IoError, Stdout, Write},
+    pin::Pin,
     sync::{Arc, Mutex, RwLock},
-    time::{SystemTime, UNIX_EPOCH},
+    time::{Duration, SystemTime, UNIX_EPOCH},
+};
+use tokio::{
+    runtime::Handle,
+    sync::oneshot::{self, Receiver, Sender},
 };
-use tokio::runtime::Runtime;
 
-pub trait Handler = Fn(Message, Arc<RwLock<Malestorm>>, Arc<Mutex<MalestormIo>>) -> Result<(), String>
-    + Send
-    + Sync
-    + 'static;
+trait Callback = FnOnce(Message) -> Result<(), String> + Send + Sync + 'static;
 
-pub struct Malestorm {
+type Handler = Arc<
+    dyn Fn(
+            Message,
+            Arc<RwLock<Maelstorm>>,
+            Arc<Mutex<MaelstormIo>>,
+        ) -> BoxFuture<'static, Result<(), String>>
+        + Send
+        + Sync,
+>;
+
+pub struct Maelstorm {
+    mutex: Mutex<()>,
     pub node: Node,
-    pub handlers: HashMap<String, Arc<dyn Handler>>,
+    pub handlers: HashMap<String, Handler>,
+    callbacks: HashMap<i64, Box<dyn Callback>>,
 }
 
 pub struct Node {
-    id: String,
-    nodes: Vec<String>,
-    counter: MonotonicCounter,
+    pub id: String,
+    pub nodes: Vec<String>,
     rng: SmallRng,
 }
-pub struct MalestormIo {
+pub struct MaelstormIo {
     stdout: Stdout,
 }
 
-impl Default for Malestorm {
+impl Default for Maelstorm {
     fn default() -> Self {
         let seed = SystemTime::now()
             .duration_since(UNIX_EPOCH)
             .expect("time went backwards??");
 
         Self {
+            mutex: Mutex::new(()),
             node: Node {
                 id: String::new(),
                 nodes: Vec::new(),
-                counter: MonotonicCounter::new(),
                 rng: SmallRng::seed_from_u64(seed.as_secs()),
             },
             handlers: HashMap::new(),
+            callbacks: HashMap::new(),
         }
     }
 }
 
-impl MalestormIo {
+impl MaelstormIo {
     fn write(&self, buf: &[u8]) -> Result<(), IoError> {
         let mut writer = self.stdout.lock();
         writer.write_all(buf)?;
@@ -63,14 +77,14 @@ impl MalestormIo {
     }
 }
 
-impl Default for MalestormIo {
+impl Default for MaelstormIo {
     fn default() -> Self {
         Self { stdout: stdout() }
     }
 }
 
-impl Malestorm {
-    pub fn run(self, runtime: Runtime, io: MalestormIo) {
+impl Maelstorm {
+    pub async fn run(self, io: MaelstormIo) {
         let program = Arc::new(RwLock::new(self));
         let io = Arc::new(Mutex::new(io));
         let stdin = stdin();
@@ -101,12 +115,29 @@ impl Malestorm {
                 }
             };
 
-            let mtype = message.body.message_type.clone();
+            if let Some(reply_msg_id) = message.body.in_reply_to {
+                let mut program = program.write().unwrap();
 
-            let handler: Arc<dyn Handler> = {
+                let callback = match program.callbacks.remove(&reply_msg_id) {
+                    Some(v) => v,
+                    None => {
+                        eprintln!("no callback for msg with reply id {}", reply_msg_id);
+                        continue;
+                    }
+                };
+
+                if let Err(e) = callback(message)
+                /* add await*/
+                {
+                    eprintln!("error in callback: {e}");
+                }
+                continue;
+            }
+
+            let handler = {
                 let program = program.read().unwrap();
 
-                match program.handlers.get(&mtype) {
+                match program.handlers.get(&message.body.message_type) {
                     Some(v) => v.clone(),
                     None => {
                         //eprintln!("no handler found for {}", message.body.message_type);
@@ -117,42 +148,24 @@ impl Malestorm {
 
             let pc = program.clone();
             let io = io.clone();
-            runtime.spawn(async move {
-                if let Err(e) = handler(message, pc, io) {
+            tokio::spawn(async move {
+                if let Err(e) = handler(message, pc, io).await {
                     eprintln!("error in serving request: {}", e);
                 }
             });
         }
     }
 
-    pub fn set_node_id(&mut self, node_id: String) {
-        self.node.id = node_id;
-    }
-
-    pub fn set_nodes(&mut self, nodes: Vec<String>) {
+    pub fn init(&mut self, node_id: String, nodes: Vec<String>) {
         self.node.nodes = nodes;
-    }
-
-    pub fn get_nodes(&self) -> Vec<String> {
-        self.node.nodes.clone()
-    }
-
-    pub fn read_counter(&self, src: &str) -> u64 {
-        self.node.counter.read(src)
-    }
-
-    pub fn write_counter(&mut self, src: &str, v: u64) {
-        self.node.counter.write(src, v);
-    }
-    pub fn add_counter(&mut self, src: &str, v: u64) {
-        self.node.counter.add(src, v);
+        self.node.id = node_id;
     }
 
     pub fn sync(
         &self,
         dest: &str,
         prev_msg: Message,
-        io: Arc<Mutex<MalestormIo>>,
+        io: Arc<Mutex<MaelstormIo>>,
     ) -> Result<(), IoError> {
         let msg = Message {
             id: Some(prev_msg.id.unwrap_or(0) + 1),
@@ -167,32 +180,91 @@ impl Malestorm {
         };
 
         let out = serde_json::to_vec(&msg)?;
-        eprintln!("wrote = {:?}", String::from_utf8_lossy(&out));
         let io = io.lock().unwrap();
         io.write(&out)?;
 
         Ok(())
     }
 
-    pub fn generate_client_id(&mut self) -> String {
-        let s2: u64 = self.node.rng.gen();
-        let s1 = &self.node.id;
-        format!("{}_{}", s1, s2)
+    pub fn register<F, Fut>(&mut self, name: &str, func: F)
+    where
+        F: Fn(Message, Arc<RwLock<Maelstorm>>, Arc<Mutex<MaelstormIo>>) -> Fut
+            + Send
+            + Sync
+            + 'static,
+        Fut: Future<Output = Result<(), String>> + Send + 'static,
+    {
+        self.handlers.insert(
+            name.to_string(),
+            Arc::new(move |a, b, c| Box::pin(func(a, b, c))),
+        );
     }
 
-    pub fn register(&mut self, name: &str, func: impl Handler) {
-        self.handlers.insert(name.to_string(), Arc::new(func));
+    pub async fn sync_rpc(
+        &mut self,
+        io: Arc<Mutex<MaelstormIo>>,
+        msg: Message,
+    ) -> Result<Message, String> {
+        let (tx, rx): (Sender<Message>, Receiver<Message>) = oneshot::channel();
+
+        self.rpc(
+            io,
+            msg,
+            Box::new(|msg| {
+                tx.send(msg)
+                    .map_err(|e| format!("error in sending to tx chan: {:?}", e))?;
+                Ok(())
+            }),
+        )
+        .map_err(|e| e.to_string())?;
+
+        match tokio::time::timeout(Duration::from_secs(2), rx).await {
+            Ok(result) => match result {
+                Ok(v) => Ok(v),
+                Err(e) => {
+                    eprintln!("sync callback error: {}", e);
+                    Err(e.to_string())
+                }
+            },
+            Err(e) => {
+                eprintln!("sync callback timeout: {}", e);
+                Err(e.to_string())
+            }
+        }
     }
 
-    pub fn send(&self, io: Arc<Mutex<MalestormIo>>, mut msg: Message) -> Result<(), IoError> {
+    fn rpc(
+        &mut self,
+        io: Arc<Mutex<MaelstormIo>>,
+        mut msg: Message,
+        handler: impl Callback,
+    ) -> Result<(), IoError> {
+        let next_msg_id = msg.body.msg_id.unwrap() + 1;
+        self.callbacks.insert(next_msg_id, Box::new(handler));
+
+        msg.body.msg_id = Some(next_msg_id);
+
+        self.send(io, msg.clone(), &msg.src)
+    }
+
+    pub fn reply(&mut self, io: Arc<Mutex<MaelstormIo>>, mut msg: Message) -> Result<(), IoError> {
+        msg.body.in_reply_to = msg.body.msg_id;
+        msg.body.msg_id = None;
+        self.send(io, msg.clone(), &msg.src)
+    }
+
+    fn send(
+        &self,
+        io: Arc<Mutex<MaelstormIo>>,
+        mut msg: Message,
+        dst: &str,
+    ) -> Result<(), IoError> {
         // Before replying, Swap src / dst in original message
         // Add the correct value for in_reply_to
 
-        std::mem::swap(&mut msg.src, &mut msg.dest);
+        msg.dest = dst.to_string();
         msg.src = self.node.id.clone();
 
-        msg.body.in_reply_to = msg.body.msg_id;
-
         let out = serde_json::to_vec(&msg)?;
         let io = io.lock().unwrap();
 
@@ -204,9 +276,62 @@ impl Malestorm {
     }
 }
 
-async fn parse_request_and_handle(
-    program: Arc<RwLock<Malestorm>>,
-    io: Arc<Mutex<MalestormIo>>,
-    buf: &[u8],
-) {
-}
+//impl Maelstorm {
+//    pub fn read_counter(
+//        &mut self,
+//        io: Arc<Mutex<MaelstormIo>>,
+//        store: &str,
+//        node_to_read: String,
+//    ) -> Result<u64, String> {
+//        let msg = Message {
+//            id: None,
+//            src: self.node.id.clone(),
+//            dest: store.to_string(),
+//            body: MessageBody {
+//                msg_id: Some(0),
+//                in_reply_to: None,
+//                message_type: "read".to_string(),
+//                message_body: serde_json::to_value(SeqKvInput {
+//                    key: node_to_read,
+//                    value: None,
+//                })
+//                .unwrap(),
+//            },
+//        };
+//        let mut result = self.sync_rpc(io, msg)?;
+//
+//        let body: SeqKvInput = serde_json::from_value(result.body.message_body.take())
+//            .map_err(|e| format!("error in parsing response body: {}", e))?;
+//
+//        Ok(body.value.unwrap())
+//    }
+//
+//    pub fn write_counter(
+//        &mut self,
+//        io: Arc<Mutex<MaelstormIo>>,
+//        store: &str,
+//        val: u64,
+//    ) -> Result<(), String> {
+//        let msg = Message {
+//            id: None,
+//            src: self.node.id.clone(),
+//            dest: store.to_string(),
+//            body: MessageBody {
+//                msg_id: Some(0),
+//                in_reply_to: None,
+//                message_type: "write".to_string(),
+//                message_body: serde_json::to_value(SeqKvInput {
+//                    key: self.node.id.clone(),
+//                    value: Some(val),
+//                })
+//                .unwrap(),
+//            },
+//        };
+//        let mut result = self.sync_rpc(io, msg)?;
+//
+//        let body: SeqKvInput = serde_json::from_value(result.body.message_body.take())
+//            .map_err(|e| format!("error in parsing response body: {}", e))?;
+//
+//        Ok(())
+//    }
+//}
diff --git a/src/main.rs b/src/main.rs
index ed7ed00..e26d49a 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -2,108 +2,100 @@
 
 use distributed_systems_flyio::{
     types::{GrowCounterReadMessage, GrowCounterUpdateMessage, InitMessage, Message},
-    Malestorm, MalestormIo,
+    Maelstorm, MaelstormIo,
 };
 use std::sync::{Arc, Mutex, RwLock};
-use tokio::runtime::Runtime;
 
-fn main() {
-    let mut program = Malestorm::default();
+async fn test(
+    msg: Message,
+    program: Arc<RwLock<Maelstorm>>,
+    io: Arc<Mutex<MaelstormIo>>,
+) -> Result<(), String> {
+    Ok(())
+}
+
+#[tokio::main]
+async fn main() {
+    let mut program = Maelstorm::default();
 
     program.register(
         "init",
         // TODO: Replace error string with a type
-        |mut msg: Message,
-         program: Arc<RwLock<Malestorm>>,
-         io: Arc<Mutex<MalestormIo>>|
-         -> Result<(), String> {
+        async |mut msg: Message,
+               program: Arc<RwLock<Maelstorm>>,
+               io: Arc<Mutex<MaelstormIo>>|
+               -> Result<(), String> {
             let message_body: InitMessage = serde_json::from_value(msg.body.message_body.take())
                 .map_err(|e| format!("error in parsing response body: {}", e))?;
 
             let mut program = program.write().unwrap();
-            program.set_node_id(message_body.node_id);
-            program.set_nodes(message_body.nodes);
+            program.init(message_body.node_id, message_body.nodes);
             msg.body.message_type = "init_ok".into();
 
             program
-                .send(io, msg)
+                .reply(io, msg)
                 .map_err(|e| format!("init: error in writing response: {}", e))
         },
     );
 
-    program.register(
-        "add",
-        |mut msg: Message,
-         program: Arc<RwLock<Malestorm>>,
-         io: Arc<Mutex<MalestormIo>>|
-         -> Result<(), String> {
-            let body: GrowCounterUpdateMessage =
-                serde_json::from_value(msg.body.message_body.take())
-                    .map_err(|e| format!("error in parsing response body: {}", e))?;
-            msg.body.message_type = "add_ok".into();
+    // program.register(
+    //     "add",
+    //     async |mut msg: Message,
+    //            program: Arc<RwLock<Maelstorm>>,
+    //            io: Arc<Mutex<MaelstormIo>>|
+    //            -> Result<(), String> {
+    //         let body: GrowCounterUpdateMessage =
+    //             serde_json::from_value(msg.body.message_body.take())
+    //                 .map_err(|e| format!("error in parsing response body: {}", e))?;
 
-            let mut program = program.write().unwrap();
-            program.add_counter(&msg.src, body.delta);
+    //         msg.body.message_type = "add_ok".into();
 
-            program
-                .send(io, msg.clone())
-                .map_err(|e| format!("add: error in writing response: {}", e))
-        },
-    );
+    //         let mut program = program.write().unwrap();
 
-    program.register(
-        "read",
-        |mut msg: Message,
-         program: Arc<RwLock<Malestorm>>,
-         io: Arc<Mutex<MalestormIo>>|
-         -> Result<(), String> {
-            msg.body.message_type = "read_ok".into();
+    //         let id = program.node.id.clone();
 
-            let program = program.read().unwrap();
-            let mut sum = 0;
-            for node in program.get_nodes() {
-                if node == msg.src {
-                    sum += program.read_counter(&node);
-                    continue;
-                }
-                // Sync first then add
+    //         //        let current = program
+    //         //            .read_counter(io.clone(), "seq-kv", id)
+    //         //            .expect("error in reading value");
 
-                program.sync(&node, msg.clone(), io.clone());
+    //         //        program.write_counter(io.clone(), "seq-kv", current + body.delta)?;
 
-                sum += program.read_counter(&msg.src);
-            }
+    //         program
+    //             .reply(io, msg)
+    //             .map_err(|e| format!("add: error in writing response: {}", e))
+    //     },
+    // );
 
-            msg.body.message_body =
-                serde_json::to_value(GrowCounterReadMessage { value: sum }).unwrap();
+    //   program.register(
+    //       "read",
+    //       async |mut msg: Message,
+    //              program: Arc<RwLock<Maelstorm>>,
+    //              io: Arc<Mutex<MaelstormIo>>|
+    //              -> Result<(), String> {
+    //           msg.body.message_type = "read_ok".into();
 
-            program
-                .send(io, msg.clone())
-                .map_err(|e| format!("read: error in writing response: {}", e))
-        },
-    );
+    //           let mut program = program.write().unwrap();
+    //           let mut sum = 0;
+    //           for node in program.node.nodes.clone() {
+    //               if *node == msg.src {
+    //                   sum += program.read_counter(io.clone(), "seq-kv", node)?;
+    //                   continue;
+    //               }
+    //               // Sync first then add
 
-    program.register(
-        "counter_sync",
-        |mut msg: Message,
-         program: Arc<RwLock<Malestorm>>,
-         io: Arc<Mutex<MalestormIo>>|
-         -> Result<(), String> {
-            msg.body.message_type = "counter_sync_ok".into();
+    //               sum += program.read_counter(io.clone(), "seq-kv", node)?;
+    //           }
 
-            let program = program.read().unwrap();
-            msg.body.message_body = serde_json::to_value(GrowCounterReadMessage {
-                value: program.read_counter(&msg.src),
-            })
-            .unwrap();
+    //           msg.body.message_body =
+    //               serde_json::to_value(GrowCounterReadMessage { value: sum }).unwrap();
 
-            program
-                .send(io, msg.clone())
-                .map_err(|e| format!("read: error in writing response: {}", e))
-        },
-    );
+    //           program
+    //               .reply(io, msg.clone())
+    //               .map_err(|e| format!("read: error in writing response: {}", e))
+    //       },
+    //   );
 
-    let io = MalestormIo::default();
-    let runtime = Runtime::new().unwrap();
+    let io = MaelstormIo::default();
 
-    program.run(runtime, io);
+    program.run(io).await;
 }
diff --git a/src/seq_kv.rs b/src/seq_kv.rs
deleted file mode 100644
index 17a7182..0000000
--- a/src/seq_kv.rs
+++ /dev/null
@@ -1,28 +0,0 @@
-use std::collections::HashMap;
-
-#[derive(Debug)]
-pub struct MonotonicCounter {
-    counter: HashMap<String, u64>,
-}
-
-impl MonotonicCounter {
-    pub fn new() -> Self {
-        Self {
-            counter: HashMap::new(),
-        }
-    }
-
-    pub fn read(&self, node: &str) -> u64 {
-        *self.counter.get(node).unwrap_or(&0)
-    }
-
-    pub fn write(&mut self, node: &str, v: u64) {
-        *self.counter.entry(node.to_string()).or_insert(0) = v;
-    }
-
-    pub fn add(&mut self, node: &str, v: u64) {
-        eprintln!("{:?}", self.counter);
-
-        *self.counter.entry(node.to_string()).or_insert(0) += v;
-    }
-}
diff --git a/src/types.rs b/src/types.rs
index f4d4d45..415f51b 100644
--- a/src/types.rs
+++ b/src/types.rs
@@ -3,6 +3,7 @@ use serde::{Deserialize, Serialize};
 #[derive(Debug, Serialize, Clone, Deserialize)]
 #[serde(deny_unknown_fields)]
 pub struct Message {
+    #[serde(skip_serializing_if = "Option::is_none")]
     pub id: Option<i64>,
     pub src: String,
     pub dest: String,
@@ -11,7 +12,9 @@ pub struct Message {
 
 #[derive(Debug, Serialize, Clone, Deserialize)]
 pub struct MessageBody {
+    #[serde(skip_serializing_if = "Option::is_none")]
     pub msg_id: Option<i64>,
+    #[serde(skip_serializing_if = "Option::is_none")]
     pub in_reply_to: Option<i64>,
 
     #[serde(rename = "type")]
@@ -41,50 +44,10 @@ pub struct GrowCounterReadMessage {
     pub value: u64,
 }
 
-#[cfg(test)]
-mod test {
-
-    use super::*;
-
-    pub fn extraneous_fields_fail() {
-        let body = "{
-  \"src\": \"c1\",
-  \"dest\": \"n1\",
-  \"body\": {
-    \"type\": \"echo\",
-    \"msg_id\": 1,
-    \"echo\": \"Please echo 35\",
-    \"extraneous\":  \"hi\"
-  }
-}";
-
-        let resp: Result<Message, serde_json::Error> = serde_json::from_str(body);
-
-        if resp.is_ok() {
-            eprintln!("successfully parsed into Message {:#?}", resp);
-        }
-
-        assert!(resp.is_err());
-    }
-
-    #[test]
-    pub fn parse_echo() {
-        let body = "{
-  \"src\": \"c1\",
-  \"dest\": \"n1\",
-  \"body\": {
-    \"type\": \"echo\",
-    \"msg_id\": 1,
-    \"echo\": \"Please echo 35\"
-  }
-}";
-
-        let resp: Result<Message, serde_json::Error> = serde_json::from_str(body);
-
-        if resp.is_err() {
-            eprintln!("failed to parsed into Echo Message {:#?}", resp);
-        }
-
-        assert!(resp.is_ok());
-    }
+#[derive(Debug, Serialize, Deserialize)]
+#[serde(deny_unknown_fields)]
+pub struct SeqKvInput {
+    pub key: String,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub value: Option<u64>,
 }