bulkWriter method
Creates a BulkWriter{@link BulkWriter}, used for performing multiple writes in parallel. Gradually ramps up writes as specified by the 500/50/5 rule.
@see https://firebase.google.com/docs/firestore/best-practices#ramping_up_traffic
@param options An options object used to configure the throttling behavior for the underlying BulkWriter.
Implementation
external BulkWriter bulkWriter([BulkWriterOptions options]);