updateMask property

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.cn/protocol-buffers/docs/reference/google.protobuf#google.protobuf.FieldMask

For example: updateMask=filter