This is the standard input/output handler.  This handler implements the
traditional Asterisk Manager interface I/O format, which can be
described as follows:

Each block of input and output should be described in terms of headers,
each terminated with \r\n (cr+lf) and consisting of a name/value pair,
and each block of headers should be terminated with two \r\n sequences:

Name1: Value1\r\nName2: Value2\r\n\r\n\r\n

The "standard" IO handler is used by astmanproxy to communicate with
Asterisk server sessions.  Clients connecting to astmanproxy can use
the "standard" handler if they wish, for either input, output or both,
or may use any other available handler.