error message fix

src/Deferred.ts

@@ -23,7 +23,7 @@ export class Deferred<T> {
 
     this._timeout = setTimeout(() => {
       callback();
-      this.reject(new TimeoutError('Operation timeout'));
+      this.reject(new TimeoutError('Operation timeout: pool acquire'));
     }, timeoutInMillis);
   }
 

test/integration/pool-test.ts

@@ -23,7 +23,7 @@ tap.test('pool expands only to max limit', (t) => {
     .then((obj) => {
       return pool.acquire().catch((e) => {
         t.ok(e instanceof TimeoutError);
-        t.ok(e.message === 'Operation timeout');
+        t.ok(e.message === 'Operation timeout: pool acquire');
         pool.release(obj);
         t.end();
       });