BigQueryIO.write() never emits successfully written records

In the following code snippet the data gets successfully inserted into BigQuery. But the "getSuccessfulInserts" Transform never returns any data. No log is written.
```

WriteResult writeResultCategory =
categoryWithHeader
.apply("BQ Insert
Category",
BigQueryIO.write()

.withCreateDisposition(CreateDisposition.CREATE_IF_NEEDED)

.withWriteDisposition(WriteDisposition.WRITE_APPEND)

.withMethod(BigQueryIO.Write.Method.STREAMING_INSERTS)
.withExtendedErrorInfo()

.withFailedInsertRetryPolicy(InsertRetryPolicy.neverRetry())

.useBeamSchema()
.to(getTableReference(tableCategory))

);

writeResultCategory
.getSuccessfulInserts()
.apply("Log
successful inserts", ParDo.of(new DoFn() {
@ProcessElement

public void process(ProcessContext c) {
LOG.info("Successfully inserted
Category: " + c.element());
}
}));
```

The problematic code might be in
```

org.apache.beam.sdk.io.gcp.bigquery.BatchedStreamingWrite.BatchAndInsertElements#finishBundle
```

The successfulInserts are never emitted from here.

Please compare this behaviour with the following method where the successfulInserts are emitted:
```

org.apache.beam.sdk.io.gcp.bigquery.BatchedStreamingWrite.InsertBatchedElements#processElement
```

Imported from Jira [BEAM-13464](https://issues.apache.org/jira/browse/BEAM-13464). Original Jira may contain additional context.
Reported by: thokie.