When true and use_topic_schema is true, any fields that are a part of the
topic schema that are not part of the BigQuery table schema are dropped
when writing to BigQuery. Otherwise, the schemas must be kept in sync and
any messages with extra fields are not written and remain in the
subscription's backlog.

bool drop_unknown_fields = 4;

Output only. An output-only field that indicates whether or not the
subscription can receive messages.

.google.pubsub.v1.BigQueryConfig.State state = 5 [(.google.api.field_behavior) = OUTPUT_ONLY];

Output only. An output-only field that indicates whether or not the
subscription can receive messages.

.google.pubsub.v1.BigQueryConfig.State state = 5 [(.google.api.field_behavior) = OUTPUT_ONLY];

The name of the table to which to write data, of the form
{projectId}.{datasetId}.{tableId}

string table = 1;

The name of the table to which to write data, of the form
{projectId}.{datasetId}.{tableId}

string table = 1;

When true, use the topic's schema as the columns to write to in BigQuery,
if it exists.

bool use_topic_schema = 2;

When true, write the subscription name, message_id, publish_time,
attributes, and ordering_key to additional columns in the table. The
subscription name, message_id, and publish_time fields are put in their own
columns while all other message properties (other than data) are written to
a JSON object in the attributes column.

bool write_metadata = 3;