fieldMask property
If include_resource is set to true, the list of fields to include in
the event payload.
Separate fields with a comma. For example, to include a Google Chat
message's sender and create time, enter
message.sender,message.createTime. If omitted, the payload includes all
fields for the resource. If you specify a field that doesn't exist for the
resource, the system ignores the field.
Optional.
Implementation
core.String? fieldMask;