performance improv for flowing output

app/bufferizedPTY.js

@@ -0,0 +1,46 @@
+module.exports = function patchPTYModule (path) {
+  const mod = require(path)
+  const oldSpawn = mod.spawn
+  mod.spawn = (file, args, opt) => {
+    let terminal = oldSpawn(file, args, opt)
+    let timeout = null
+    let buffer = ''
+    let lastFlush = 0
+    let nextTimeout = 0
+
+    const maxWindow = 250
+    const minWindow = 50
+
+    function flush () {
+        if (buffer) {
+            terminal.emit('data-buffered', buffer)
+        }
+        lastFlush = Date.now()
+        buffer = ''
+    }
+
+    function reschedule () {
+        if (timeout) {
+            clearTimeout(timeout)
+        }
+        nextTimeout = Date.now() + minWindow
+        timeout = setTimeout(() => {
+            timeout = null
+            flush()
+        }, minWindow)
+    }
+
+    terminal.on('data', data => {
+        buffer += data
+        if (Date.now() - lastFlush > maxWindow) {
+            flush()
+        } else {
+            if (Date.now() > nextTimeout - (minWindow / 10)) {
+                reschedule()
+            }
+        }
+    })
+    return terminal
+  }
+  return mod
+}