Client.Committype t = Raw.Client.Commit.t Capnp_rpc_lwt.Capability.tA single commit being tested.
job_of_variant t is the (most recent) OCurrent job for this variant.
refs t is the list of Git references that have this commit as their head.
val status : 
  t ->
  ([ `Not_started | `Pending | `Failed | `Passed ],
    [> `Capnp of Capnp_rpc.Error.t | `Msg of string ])
    Lwt_result.tstatus t is the result of the most-recent 'summarise' step on this commit.