Package dbms_pipe
=================
This packege is emulation of Oracle's package dbms_pipe. It's very simple and
basic now. Use only one pipe with size one.

try:

session A | session B
----------------------------------------------------------
pack_message('a');
pack_message('b');
send_message('blabla',1);
receive_message('blabla',1);
unpack_message();
unpack_message();