Turn off Nagle algorithm to decrease latency.

This is safe because of the way writes are performed: for each transmission,
all outgoing messages are concatenated in memory and only a single write()
syscall is made.

src/tcpsockets/NetworkStream.h

@@ -30,6 +30,7 @@ class NetworkStream {
 
   virtual llvm::StringRef getPeerIP() const = 0;
   virtual int getPeerPort() const = 0;
+  virtual void setNoDelay() = 0;
 
   NetworkStream(const NetworkStream&) = delete;
   NetworkStream& operator=(const NetworkStream&) = delete;