Add debug code to trace socket state transitions and fix bug in response parser where a space was consumed twice

src/socket.h

@@ -331,3 +331,7 @@ int socket_is_secure(SocketManager *sm, SocketHandle handle);
 
 // Set the user pointer of a socket
 int socket_set_user(SocketManager *sm, SocketHandle handle, void *user);
+
+// Returns true iff the socket is ready for reading or
+// writing.
+bool socket_ready(SocketManager *sm, SocketHandle handle);