class client :Netchannels.in_obj_channel -> Netchannels.out_obj_channel ->object..end
client implements the POP3 protocol. Client objects
 are created by
  new client in_ch out_ch 
 where in_ch is an input channel representing the input direction of
 the TCP stream, and where out_ch is an output channel representing
 the output direction of the TCP stream.method state : statemethod quit : unit -> unit`Transaction state, the server will attempt
 to remove all messages marked as deleted before closing its 
 side of the connection.method close : unit -> unitmethod user : user:string -> unitpass command.method pass : pass:string -> unitpass.method apop : user:string -> pass:string -> unituser/pass command sequence.method stat : unit -> int * int * string(count,size,ext) where count is the number of messages in 
 the mailbox, size is the size of the mailbox in octets, 
 and ext is any server extension data.method list : ?msgno:int -> unit -> (int, int * string) Hashtbl.t(size,ext) where
 size is the size of the message in octets, and ext is any 
 server extension data.method retr : msgno:int -> Netchannels.in_obj_channelmethod dele : msgno:int -> unitmethod noop : unit -> unitmethod rset : unit -> unitmethod top : ?lines:int -> msgno:int -> unit -> Netchannels.in_obj_channelmethod uidl : ?msgno:int -> unit -> (int, string) Hashtbl.tmethod stls : peer_name:string option -> Netsys_crypto_types.tls_config -> unitErr_state if TLS is unavailable on the server.
        STLS is specified in RFC 2595.
method tls_endpoint : Netsys_crypto_types.tls_endpoint optionSTARTTLS)method tls_session_props : Nettls_support.tls_session_props optionSTARTTLS)