feat(infra): new doc sync engine (#6205)

https://github.com/toeverything/AFFiNE/blob/eyhn/feat/new-sync/packages/common/infra/src/workspace/engine/doc/README.md

packages/common/infra/src/utils/async-lock.ts

@@ -0,0 +1,20 @@
+export class AsyncLock {
+  private _lock = Promise.resolve();
+
+  async acquire() {
+    // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
+    let release: () => void = null!;
+    const nextLock = new Promise<void>(resolve => {
+      release = resolve;
+    });
+
+    await this._lock;
+    this._lock = nextLock;
+    return {
+      release,
+      [Symbol.dispose]: () => {
+        release();
+      },
+    };
+  }
+}

packages/common/infra/src/utils/index.ts

@@ -1,3 +1,4 @@
+export * from './async-lock';
 export * from './async-queue';
 export * from './merge-updates';
 export * from './object-pool';