MessageWrapper.Object
type (!'cap, !'a) t = ( 'cap, 'a ) Capnp.RPC.None(Capnp.BytesMessage).Object.t =
| None
| List of 'cap ListStorage.t
| Struct of ( 'cap, 'a ) StructStorage.t
| Capability of Capnp__MessageSig.Uint32.t