Dedicated method for getting the next seq from the buffer

Author: blast-hardcheese

src/replit_river/message_buffer.py

@@ -37,6 +37,11 @@ def put(self, message: TransportMessage) -> None:
             raise MessageBufferClosedError("message buffer is closed")
         self.buffer.append(message)
 
+    def get_next_sent_seq(self) -> int | None:
+        if self.buffer:
+            return self.buffer[0].seq
+        return None
+
     async def peek(self) -> TransportMessage | None:
         """Peek the first message in the buffer, returns None if the buffer is empty."""
         async with self._lock:

src/replit_river/session.py

@@ -185,10 +185,7 @@ async def get_next_expected_seq(self) -> int:
 
     async def get_next_sent_seq(self) -> int:
         """Get the next sequence number that the client will send."""
-        nextMessage = await self._buffer.peek()
-        if nextMessage:
-            return nextMessage.seq
-        return self._seq_manager.get_seq()
+        return self._buffer.get_next_sent_seq() or self._seq_manager.get_seq()
 
     async def get_next_expected_ack(self) -> int:
         """Get the next expected ack that the client expects."""