feat: Add isDone to JsonWriter to indicate a JsonWriter is no longer usable and needs to be recreated. (#1978)

* . * . * 🦉 Updates from OwlBot post-processor See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md --------- Co-authored-by: Owl Bot <gcf-owl-bot[bot]@users.noreply.github.com>

Author: yirutang

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

@@ -382,6 +382,15 @@ public void close() {
  this.streamWriter.close();
  }
 
+ /**
+ * @return if a Json writer can no longer be used for writing. It is due to either the
+ * JsonStreamWriter is explicitly closed or the underlying connection is broken when
+ * connection pool is not used. Client should recreate JsonStreamWriter in this case.
+ */
+ public boolean isDone() {
+ return this.streamWriter.isDone();
+ }
+
  public static final class Builder {
  private String streamName;
  private BigQueryWriteClient client;

google-cloud-bigquerystorage/src/test/java/com/google/cloud/bigquery/storage/v1/JsonStreamWriterTest.java

@@ -1139,6 +1139,14 @@ public void testWriterId()
  Assert.assertNotEquals(writer1.getWriterId(), writer2.getWriterId());
  }
 
+ @Test
+ public void testIsDone() throws DescriptorValidationException, IOException, InterruptedException {
+ JsonStreamWriter writer1 = getTestJsonStreamWriterBuilder(TEST_STREAM, TABLE_SCHEMA).build();
+ Assert.assertFalse(writer1.isDone());
+ writer1.close();
+ Assert.assertTrue(writer1.isDone());
+ }
+
  private AppendRowsResponse createAppendResponse(long offset) {
  return AppendRowsResponse.newBuilder()
  .setAppendResult(