A structure for the output.
An error message when the operation fails.
The state of a query previously submitted. The possible states are:
PENDING: the query is pending.
WORKUNITS_AVAILABLE: some work units are ready for retrieval and execution.
FINISHED: the query planning finished successfully, and all work units are ready for retrieval and execution.
ERROR: an error occurred with the query, such as an invalid query ID or a backend error.