Tezos_baking_015_PtLimaPt.Baking_vdfSourceval start_vdf_worker :
Tezos_client_015_PtLimaPt.Protocol_client_context.full ->
canceler:Lwt_canceler.t ->
Tezos_protocol_015_PtLimaPt.Protocol.Alpha_context.Constants.t ->
Tezos_shell_services.Chain_services.chain ->
unit Tezos_base.TzPervasives.tzresult Lwt.t