Required. The updated sink, whose name is the same identifier
that appears as part of sink_name.
Optional. Field mask that specifies the fields in sink
that need an update. A sink field will be overwritten if, and
only if, it is in the update mask. name and output only
fields cannot be updated. An empty updateMask is temporarily
treated as using the following mask for backwards
compatibility purposes: destination,filter,includeChildren At
some point in the future, behavior will be removed and
specifying an empty updateMask will be an error. For a
detailed FieldMask definition, see
https://developers.google.com/protocol-buffers/docs/reference/
google.protobuf#google.protobuf.FieldMask Example:
updateMask=filter.
