Fix (maybe) issue about first frame being dropped on new client

src/net/transport/mod.rs

@@ -77,6 +77,7 @@ impl Transport {
     }
 
     /// Splits transport into read and write halves
+    #[allow(dead_code)]
     pub fn split(self) -> (TransportReadHalf, TransportWriteHalf) {
         let key = self.key;
         let parts = self.inner.into_parts();
@@ -86,6 +87,13 @@ impl Transport {
         //       into the new framed instances. This means we are dropping our old buffer
         //       data (I think). This shouldn't be a problem since we are splitting
         //       immediately, but it would be nice to cover this properly one day
+        //
+        //       From initial testing, this may actually be a problem where part of a frame
+        //       arrives so quickly that we lose the first message. So recommendation for
+        //       now is to create the frame halves separately first so we have no
+        //       chance of building a partial frame
+        //
+        //       See https://github.com/tokio-rs/tokio/issues/4000
         let t_read = TransportReadHalf {
             inner: FramedRead::new(read_half, parts.codec),
             key: Arc::clone(&key),
@@ -106,6 +114,14 @@ pub struct TransportWriteHalf {
 }
 
 impl TransportWriteHalf {
+    /// Creates a new transport write half directly from a TCP write half
+    pub fn new(write_half: tcp::OwnedWriteHalf, key: Arc<SecretKey>) -> Self {
+        Self {
+            inner: FramedWrite::new(write_half, DistantCodec),
+            key,
+        }
+    }
+
     /// Sends some data across the wire
     pub async fn send<T: Serialize>(&mut self, data: T) -> Result<(), TransportError> {
         // Serialize, encrypt, and then (TODO) sign
@@ -127,6 +143,14 @@ pub struct TransportReadHalf {
 }
 
 impl TransportReadHalf {
+    /// Creates a new transport read half directly from a TCP read half
+    pub fn new(read_half: tcp::OwnedReadHalf, key: Arc<SecretKey>) -> Self {
+        Self {
+            inner: FramedRead::new(read_half, DistantCodec),
+            key,
+        }
+    }
+
     /// Receives some data from out on the wire, waiting until it's available,
     /// returning none if the transport is now closed
     pub async fn receive<T: DeserializeOwned>(&mut self) -> Result<Option<T>, TransportError> {

src/subcommand/listen/mod.rs

@@ -1,6 +1,6 @@
 use crate::{
     data::{Request, Response},
-    net::{Transport, TransportReadHalf, TransportWriteHalf},
+    net::{TransportReadHalf, TransportWriteHalf},
     opt::{CommonOpt, ConvertToIpAddrError, ListenSubcommand},
 };
 use derive_more::{Display, Error, From};
@@ -132,7 +132,9 @@ async fn run_async(cmd: ListenSubcommand, _opt: CommonOpt, is_forked: bool) -> R
 
         // Build a transport around the client, splitting into read and write halves so we can
         // handle input and output concurrently
-        let (t_read, t_write) = Transport::new(client, Arc::clone(&key)).split();
+        let (r, w) = client.into_split();
+        let t_read = TransportReadHalf::new(r, Arc::clone(&key));
+        let t_write = TransportWriteHalf::new(w, Arc::clone(&key));
         let (tx, rx) = mpsc::channel(cmd.max_msg_capacity as usize);
 
         // Spawn a new task that loops to handle requests from the client