assert failure faraday.ml:377 using Async

[roddyyaga]

I'm trying to use faraday with Async like so:

open Async

let handle fd =
  let ic = Reader.create fd in
  let writev = Faraday_async.writev_of_fd fd in
  let output_buffer = Faraday.create 16 in
  let write_output x =
    Faraday_async.serialize output_buffer
      ~yield:(fun buffer -> my_serialize_function buffer x |> return)
      ~writev
  in
  Angstrom_async.parse_many parse_function
    (fun parsed -> parsed |> my_processing_function |> write_output)
    ic
  >>| Result.get_ok

let create_server port =
  Tcp.Server.create_sock_inet ~on_handler_error:`Raise
    (Tcp.Where_to_listen.of_port port) (fun _address socket ->
      handle (Socket.fd socket))

but I get this error any time I try to connect:

((monitor.ml.Error "Assert_failure lib/faraday.ml:377:4"
    ("Raised at file \"async/faraday_async.ml\", line 30, characters 6-15"
     "Called from file \"src/deferred1.ml\", line 17, characters 40-45"
     "Called from file \"src/job_queue.ml\", line 167, characters 6-47"
     "Caught by monitor Tcp.Server.create_sock_inet"))

Any idea why this might be happening?