[Feature Request]: Support SchemaUpdateOptions for BigQueryIO Storage Write API

[carlpayne]

What would you like to happen?

When writing data with BigQueryIO using BigQueryIO.Write.Method.STORAGE_API_AT_LEAST_ONCE or BigQueryIO.Write.Method.STORAGE_WRITE_API, it would be very useful to be able to specify one or more SchemaUpdateOption values via .withSchemaUpdateOptions.

Currently this only works for BigQueryIO.Write.Method.FILE_LOADS, which means that for other insert methods new fields are either ignored (if ignoreUnknownValues is set), or fail to insert. In our use case, we are streaming Avro records from Kafka to BigQuery, with the schema constantly changing (mostly new fields). Having BigQueryIO manage this would be a huge benefit.

Issue Priority

Priority: 3

Issue Component

Component: io-java-gcp

[kennknowles]

CC @reuvenlax @scwhittle

[kennknowles]

@johnjcasey