CThreadval prepare_in_channel_for_thread_friendly_io : Stdlib.in_channel -> thread_icval thread_friendly_input_value : thread_ic -> 'aval thread_friendly_read : 
  thread_ic ->
  Stdlib.Bytes.t ->
  off:int ->
  len:int ->
  intval thread_friendly_really_read : 
  thread_ic ->
  Stdlib.Bytes.t ->
  off:int ->
  len:int ->
  unitval thread_friendly_really_read_line : thread_ic -> string