-type close_send() :: fun((stream()) -> stream()).

-type init_req() :: fun((stream(), Opts :: map()) -> stream()).

-type parse_msg() ::
          fun((stream(), Buf :: binary()) ->
                  {ok, stream(), Response :: map(), Rest :: binary()} | more | {error, any()}).

-type recv_header() :: fun((stream(), Timeout :: timeout()) -> {ok, stream()} | {error, any()}).

-type recv_msg() ::
          fun((stream(), Timeout :: timeout(), Buf :: binary()) ->
                  {ok, stream(), Response :: map(), Rest :: binary()} | {error, any()}).

-type send_msg() :: fun((stream(), Request :: map(), IsFin :: fin | nofin) -> stream()).

-type stream() ::
          #stream{channel :: egrpc_stub:channel(),
                  grpc :: egrpc:grpc(),
                  headers :: [{binary(), binary()}],
                  stream_ref :: undefined | gun:stream_ref(),
                  encoding :: identity | gzip,
                  encoder :: fun((any()) -> binary()),
                  decoder :: fun((binary()) -> any()),
                  stream_interceptor_chain ::
                      #stream_interceptor_chain{init_req :: init_req(),
                                                send_msg :: send_msg(),
                                                close_send :: close_send(),
                                                recv_header :: recv_header(),
                                                recv_msg :: recv_msg(),
                                                parse_msg :: parse_msg()} |
                      undefined,
                  stream_interceptor_states :: map(),
                  info :: term()}.