class type mime_body =object..end
 The value of the body can be set either by a string, or by writing
 to an object channel. Both ways are possible independently of where
 the value is stored, in-memory, or as external file.
Netmime.mime_body_ro    Supports all these read access method, toomethod ro : boolmethod set_value : string -> unitImmutable will be raised.
 The passed string must be in decoded form. When the body is
 stored in an external file, the file is overwritten.
method open_value_wr : unit -> Netchannels.out_obj_channelImmutable will be raised.
 For example, to copy the file f into the value:
 
 
 let ch = body # open_value_wr() in
 let f_ch = new Netchannels.input_file f in
 ch # output_channel f_ch;
 f_ch # close_in();
 ch # close_out();