refactor(core): remove useless Webpack wait plugin (#10579)

packages/docusaurus/src/webpack/plugins/WaitPlugin.ts

@@ -1,56 +0,0 @@
-/**
- * Copyright (c) Facebook, Inc. and its affiliates.
- *
- * This source code is licensed under the MIT license found in the
- * LICENSE file in the root directory of this source tree.
- */
-
-import fs from 'fs-extra';
-import type {Compiler} from 'webpack';
-
-type WaitPluginOptions = {
-  filepath: string;
-};
-
-export default class WaitPlugin {
-  filepath: string;
-
-  constructor(options: WaitPluginOptions) {
-    this.filepath = options.filepath;
-  }
-
-  apply(compiler: Compiler): void {
-    // Before finishing the compilation step
-    compiler.hooks.make.tapPromise('WaitPlugin', () => waitOn(this.filepath));
-  }
-}
-
-// This is a re-implementation of the algorithm used by the "wait-on" package
-// https://github.com/jeffbski/wait-on/blob/master/lib/wait-on.js#L200
-async function waitOn(filepath: string): Promise<void> {
-  const pollingIntervalMs = 300;
-  const stabilityWindowMs = 750;
-
-  let lastFileSize = -1;
-  let lastFileTime = -1;
-
-  for (;;) {
-    let size = -1;
-    try {
-      size = (await fs.stat(filepath)).size;
-    } catch (err) {}
-
-    if (size !== -1) {
-      if (lastFileTime === -1 || size !== lastFileSize) {
-        lastFileSize = size;
-        lastFileTime = performance.now();
-      } else if (performance.now() - lastFileTime >= stabilityWindowMs) {
-        return;
-      }
-    }
-
-    await new Promise((resolve) => {
-      setTimeout(resolve, pollingIntervalMs);
-    });
-  }
-}