fix: Add back the accidentally removed background executor provider (#1899)

* feat: Split writer into connection worker and wrapper, this is a prerequisite for multiplexing client * feat: add connection worker pool skeleton, used for multiplexing client * feat: add Load api for connection worker for multiplexing client * feat: add multiplexing support to connection worker. We will treat every new stream name as a switch of destinationt * 🦉 Updates from OwlBot post-processor See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md * Updates from OwlBot post-processor See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md * 🦉 Updates from OwlBot post-processor See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md * feat: port the multiplexing client core algorithm and basic tests also fixed a tiny bug inside fake bigquery write impl for getting thre response from offset * 🦉 Updates from OwlBot post-processor See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md * feat: wire multiplexing connection pool to stream writer * feat: some fixes for multiplexing client * feat: fix some todos, and reject the mixed behavior of passed in client or not * feat: fix the bug that we may peek into the write_stream field but it's possible the proto schema does not contain this field * 🦉 Updates from OwlBot post-processor See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md * feat: fix the bug that we may peek into the write_stream field but it's possible the proto schema does not contain this field * feat: add getInflightWaitSeconds implementation * feat: Add schema comparision in connection loop to ensure schema update for the same stream name can be notified * 🦉 Updates from OwlBot post-processor See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md * feat: add schema update support to multiplexing * fix: fix windows build bug: windows Instant resolution is different with linux * fix: fix another failing tests for windows build * fix: fix another test failure for Windows build * feat: Change new thread for each retry to be a thread pool to avoid create/tear down too much threads if lots of retries happens * 🦉 Updates from OwlBot post-processor See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md * fix: add back the background executor provider that's accidentally removed Co-authored-by: Owl Bot <gcf-owl-bot[bot]@users.noreply.github.com>

Author: GaoleMeng

google-cloud-bigquerystorage/src/main/java/com/google/cloud/bigquery/storage/v1/StreamWriter.java

@@ -279,6 +279,7 @@ private BigQueryWriteClient getBigQueryWriteClient(Builder builder) throws IOExc
  BigQueryWriteSettings.newBuilder()
  .setCredentialsProvider(builder.credentialsProvider)
  .setTransportChannelProvider(builder.channelProvider)
+ .setBackgroundExecutorProvider(builder.executorProvider)
  .setEndpoint(builder.endpoint)
  .build();
  testOnlyClientCreatedTimes++;