fix(cleanup): remove scheduler related code

src/flush-microtasks.js

@@ -1,6 +1,3 @@
-import React from 'react'
-import satisfies from 'semver/functions/satisfies'
-
 /* istanbul ignore file */
 // the part of this file that we need tested is definitely being run
 // and the part that is not cannot easily have useful tests written
@@ -18,9 +15,6 @@ function getIsUsingFakeTimers() {
   )
 }
 
-const globalObj = typeof window === 'undefined' ? global : window
-let Scheduler = globalObj.Scheduler
-
 let didWarnAboutMessageChannel = false
 let enqueueTask
 
@@ -32,8 +26,6 @@ try {
   // assuming we're in node, let's try to get node's
   // version of setImmediate, bypassing fake timers if any.
   enqueueTask = nodeRequire.call(module, 'timers').setImmediate
-  // import React's scheduler so we'll be able to schedule our tasks later on.
-  Scheduler = nodeRequire.call(module, 'scheduler')
 } catch (_err) {
   // we're in a browser
   // we can't use regular timers because they may still be faked
@@ -55,28 +47,9 @@ try {
           'if you encounter this warning.',
       )
     }
-
   }
 }
 
-const isModernScheduleCallbackSupported = Scheduler && satisfies(React.version, '>16.8.6', {
-  includePrerelease: true,
-})
-
-function scheduleCallback(cb) {
-  const NormalPriority = Scheduler
-    ? Scheduler.NormalPriority || Scheduler.unstable_NormalPriority
-    : null
-
-  const scheduleFn = Scheduler
-    ? Scheduler.scheduleCallback || Scheduler.unstable_scheduleCallback
-    : callback => callback()
-
-  return isModernScheduleCallbackSupported
-    ? scheduleFn(NormalPriority, cb)
-    : scheduleFn(cb)
-}
-
 export default function flushMicroTasks() {
   return {
     then(resolve) {
@@ -87,7 +60,7 @@ export default function flushMicroTasks() {
         jest.advanceTimersByTime(0)
         resolve()
       } else {
-        scheduleCallback(() => enqueueTask(resolve))
+        enqueueTask(resolve)
       }
     },
   }