[zeromq-dev] xreq sockets

[Serge Aleynikov]

Are there any examples or documentation of XREQ and XREP sockets?  I 
tried switching from REQ to XREQ and see that it affects a change in 
payload:

Message: "this is a test"

When using REQ sockets, on the REP side I get the following bytes:
116,104,105,115,32,105,115,32,97,32,116,101,115,116

which is expected.  However with XREQ sockets I get 18 extra bytes:

17,0,244,78,69,38,83,62,73,47,147,218,207,209,36,199,233,150,
116,104,105,115,32,105,115,32,97,32,116,101,115,116

I suppose 17 indicates the size, but what is the rest that precedes the 
expected message?

Serge