Emit drain and stop IOWatcher even on empty buffer

src/node_io_watcher.cc

@@ -374,8 +374,7 @@ void IOWatcher::Dump() {
       }
     }
 
-    if (to_write == 0) continue;
-
+    if (to_write > 0) {
       ssize_t written;
 
       if (unix_socket) {
@@ -523,6 +522,8 @@ void IOWatcher::Dump() {
 
       // Set the queue size.
       watcher->Set(queue_size_sym, Integer::NewFromUnsigned(queue_size));
+    }
+
 
     // Finished dumping the buckets.
     //