TextIO.Write appear success but request not sent to Google Cloud Storage

Google Cloud Dataflow is being used to run Apache Beam job.

from the Dataflow log, the file operation appear to be success.

Will copy temporary file FileResult{tempFilename=gs://xxxxxx, shard=0, window=org.apache.beam.sdk.transforms.windowing.GlobalWindow@xxxxx, paneInfo=PaneInfo{isFirst=true, isLast=true, timing=ON_TIME, index=0, onTimeIndex=0}} to final location gs://xxxx/20190211.csv

But when I checked GCS and its log, there was no put or post request during that time.

This issue happened intermittently. The file is copied successfully sometimes, after retry.

I have checked the relevant Beam source code
https://github.com/apache/beam/blob/c96b096b77c324b886ab94aebcf320976002c0d4/sdks/java/core/src/main/java/org/apache/beam/sdk/io/FileBasedSink.java#L763
and
https://github.com/apache/beam/blob/c96b096b77c324b886ab94aebcf320976002c0d4/sdks/java/core/src/main/java/org/apache/beam/sdk/io/FileSystems.java#L304

seems like in rename() method, there are multiple conditions that the method would return without Exception and appear as "success" in log.

Is there any bug in these Beam methods or I should check for error in my code?

```

TextIO.write().withoutSharding().to(options.getOutFilePath()));

```

Imported from Jira [BEAM-6707](https://issues.apache.org/jira/browse/BEAM-6707). Original Jira may contain additional context.
Reported by: drakoleat.