Update uSocketsMock.c

fuzzing/uSocketsMock.c

@@ -123,7 +123,7 @@ struct us_socket_context_t *us_create_child_socket_context(int ssl, struct us_so
 }
 
 int us_socket_write(int ssl, struct us_socket_t *s, const char *data, int length, int msg_more) {
-
+    return length;
 }
 
 void us_socket_timeout(int ssl, struct us_socket_t *s, unsigned int seconds) {
@@ -183,4 +183,4 @@ void us_loop_read_mocked_data(struct us_loop_t *loop, char *data, unsigned int s
 
     /* Free the socket */
     free(s);
-}
+}