Tezos_baking_alpha.Baking_vdfval start_vdf_worker :
Tezos_client_alpha.Protocol_client_context.full ->
canceler:Lwt_canceler.t ->
Tezos_protocol_alpha.Protocol.Alpha_context.Constants.t ->
Tezos_shell_services.Chain_services.chain ->
unit Tezos_base.TzPervasives.tzresult Lwt.t