ErrBarrierExists is returned when a job ordering barrier exists for the job's ordering key.

ErrContextCancelled is returned when the context is cancelled.

ErrDestinationThrottled is returned when the destination is being throttled.

ErrJobBackoff is returned when the job is backoffed.

ErrJobOrderBlocked is returned when the job is blocked by another job discarded by the router in the same loop.

ErrParamsUnmarshal is returned when it is not possible to unmarshal the job parameters.

ErrWorkerNoSlot is returned when the worker doesn't have an available slot.

DestinationJobT holds the job to be sent to destination and metadata of all the router jobs from which this job is cooked up.

JobMetadataT holds the job metadata.

RouterJobT holds the router job and its related metadata.

TransformMessageT is used to pass message to the transformer workers.