Negotiation
===========

Before any client is allowed to talk to other clients, it must
register itself with the bus. Currently this is done by sending the
"org.freedesktop.DBus.Hello" message to the "org.freedesktop.DBus"
service. This service is provided by the D-Bus daemon and therefore
always exists. 

The first field of the Hello message is a string containing a
name. The bus driver will then append a dash and a number to make the
client name unique and send a "Welcome" message back. It could also
send an "Error" message back, for example if the client tries to
register twice.