src: improve StreamBase write throughput

Improve performance by transferring information about write status
to JS through an `AliasedBuffer`, rather than object properties
set from C++.

PR-URL: https://github.com/nodejs/node/pull/23843
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Anatoli Papirovski <apapirovski@mac.com>

1 files changed, 3 insertions, 2 deletions

diff --git a/lib/internal/child_process.js b/lib/internal/child_process.js
index a2478ec69d..ddb7e58d7c 100644
--- a/lib/internal/child_process.js
+++ b/lib/internal/child_process.js
@@ -26,6 +26,7 @@ const {
   WriteWrap,
   kReadBytesOrError,
   kArrayBufferOffset,
+  kLastWriteWasAsync,
   streamBaseState
 } = internalBinding('stream_wrap');
 const { Pipe, constants: PipeConstants } = internalBinding('pipe_wrap');
@@ -716,10 +717,10 @@ function setupChannel(target, channel) {
     }
 
     var req = new WriteWrap();
-    req.async = false;
 
     var string = JSON.stringify(message) + '\n';
     var err = channel.writeUtf8String(req, string, handle);
+    var wasAsyncWrite = streamBaseState[kLastWriteWasAsync];
 
     if (err === 0) {
       if (handle) {
@@ -729,7 +730,7 @@ function setupChannel(target, channel) {
           obj.postSend(message, handle, options, callback, target);
       }
 
-      if (req.async) {
+      if (wasAsyncWrite) {
         req.oncomplete = function() {
           control.unref();
           if (typeof callback === 'function')