class lift_rec_out_channel :?start_pos_out:int -> rec_out_channel ->out_obj_channel
pos_out and the methods from compl_out_channel 
 by calling the methods of rec_out_channel. 
 There is no additional buffering.
 The method pos_out is implemented by counting the number of octets
 read by the output method.
start_pos_out : The initial value of the counter for pos_out.
   Defaults to 0.