Optional
Echoed back in the events this request produces, so they can be matched to their call. Unset means no correlation, and 0 is reserved for the same meaning on the result, so ids start at 1.
Echoed back in the events this request produces, so they can be matched to their call. Unset means no correlation, and 0 is reserved for the same meaning on the result, so ids start at 1.