class client : Netchannels.in_obj_channel -> Netchannels.out_obj_channel -> object .. end
The class 
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 : state
Current state of this session.
method quit : unit -> unit
Requests the server to end this session. If the session is 
 currently in the `Transaction state, the server will attempt
 to remove all messages marked as deleted before closing its 
 side of the connection.
method user : user:string -> unit
Specifies the name of the mailbox the client would like to open
       using plain-text authentication. Normal completion of this function
       should be followed by the pass command.
method pass : pass:string -> unit
Authenticates a user with the plain-text password pass.
method apop : user:string -> pass:string -> unit
Specifies the user and password using APOP authentication.
 APOP is a more secure method of authentication than what is
 provided by the user/pass command sequence.
method stat : unit -> int * int * string
Returns information about the current mailbox as tuple
 (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
Returns the scan listing for an optional message number or
 for all messages in the current mailbox. The result is a hash
 table that maps a message number to a tuple (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_channel
Retrieves a message from the server.
method dele : msgno:int -> unit
Marks the message number of the current mailbox for deletion.
method noop : unit -> unit
Pings the server to keep the session alive.
method rset : unit -> unit
Unmarks any messages that have previously been marked as
 deleted.
method top : ?lines:int -> msgno:int -> unit -> Netchannels.in_obj_channel
Returns the message header plus a limited number of lines
 of the message body. The default body length is 0 lines.
method uidl : ?msgno:int -> unit -> (int, string) Hashtbl.t
Returns the unique identifier(s) for an optional message number
 or for all messages in the current mailbox. The result is a
 hash table that maps a message number to its unique id.