Merge pull request xtermjs#4145 from Tyriar/microtask_server

Optimize critical I/O path for input latency

Author: Tyriar

demo/server.js

@@ -86,7 +86,7 @@ function startServer() {
       return (data) => {
         s += data;
         if (!sender) {
-          sender = setTimeout(() => {
+          sender = queueMicrotask(() => {
             socket.send(s);
             s = '';
             sender = null;
@@ -103,7 +103,7 @@ function startServer() {
         buffer.push(data);
         length += data.length;
         if (!sender) {
-          sender = setTimeout(() => {
+          sender = queueMicrotask(() => {
             socket.send(Buffer.concat(buffer, length));
             buffer = [];
             sender = null;

src/common/input/WriteBuffer.ts

@@ -105,7 +105,7 @@ export class WriteBuffer {
     // schedule chunk processing for next event loop run
     if (!this._writeBuffer.length) {
       this._bufferOffset = 0;
-      setTimeout(() => this._innerWrite());
+      queueMicrotask(() => this._innerWrite());
     }
 
     this._pendingData += data.length;
@@ -217,7 +217,7 @@ export class WriteBuffer {
         this._callbacks = this._callbacks.slice(this._bufferOffset);
         this._bufferOffset = 0;
       }
-      setTimeout(() => this._innerWrite());
+      queueMicrotask(() => this._innerWrite());
     } else {
       this._writeBuffer.length = 0;
       this._callbacks.length = 0;