Revert "WIP: Fix race condition in reporting plugin"

This reverts commit 771f0b2befc208d28b8012172d7447acc29068d2.

x-pack/plugins/reporting/server/lib/tasks/execute_report.ts

@@ -10,9 +10,8 @@ import type { Logger } from '@kbn/core/server';
 import moment from 'moment';
 import * as Rx from 'rxjs';
 import { timeout } from 'rxjs/operators';
-import { Writable } from 'stream';
-import { finished } from 'stream/promises';
-import { setImmediate } from 'timers/promises';
+import { finished, Writable } from 'stream';
+import { promisify } from 'util';
 import type {
   RunContext,
   TaskManagerStartContract,
@@ -378,16 +377,7 @@ export class ExecuteReportTask implements ReportingTask {
 
             stream.end();
 
-            // FIXME: Wait for the stream to end so that we don't trigger `ERR_STREAM_PREMATURE_CLOSE` errors when calling `finished` below (see https://github.com/nodejs/node/issues/45281). Before merging this should be fixed!
-            await (async function pendingCallbacks() {
-              if ((stream as any)._writableState.pendingcb > 0) {
-                await setImmediate();
-                await pendingCallbacks();
-              }
-            })();
-
-            // FIXME: This is where the "Premature close" error is thrown!
-            await finished(stream, { readable: false });
+            await promisify(finished)(stream, { readable: false });
 
             report._seq_no = stream.getSeqNo()!;
             report._primary_term = stream.getPrimaryTerm()!;