Structure of a session:


session {
	-- properties --
	conn -- the tcp connection
	notopen -- true if stream has not been initiated, removed after receiving <stream:steam>
	priority -- the resource priority, default: 0
	type -- the connection type. Valid values include:
			-- "c2s_unauthed" - connection has not been authenticated yet
			-- "c2s" - from a local client to the server
	username -- the node part of the client's jid (not defined before auth)
	host -- the host part of the client's jid (not defined before stream initiation)
	resource -- the resource part of the client's full jid (not defined before resource binding)
	
	-- methods --
	send(x) -- converts x to a string, and writes it to the connection
}