OptionaletaOptionaletaLower bound of the worker's ETA confidence interval, in seconds.
OptionaletaWorker's time-remaining estimate in seconds, when reported with the step.
0 means the worker had no estimate for this step.
OptionalprogressOptionalstepOptionalstep
Upper bound of the worker's ETA confidence interval, in seconds.
0(withetaMin: 0) means the worker had no interval for this step.