google.protobuf.duration_pb2.Duration
Optional. Amount of time executable has to complete. See
JSON representation of
Duration __.
If this field is set with a value less than the RPC
deadline, and the execution of your query hasn't finished in
the specified execution timeout, you will get a response
with partial result. Otherwise, your query's execution will
continue until the RPC deadline. If it's not finished until
then, you will get a DEADLINE_EXCEEDED error.
Default is empty.