If we could pass an a{sv} of immutable properties to a TpChannel at construct time, this would speed up construction considerably when the Requests API becomes available - we could pre-populate a lot of the cached information.

The API could perhaps be:

TpChannel *tp_channel_new_with_properties (TpConnection *, const GHashTable *)

This might also be a good time to extend the "channel-ready" guarantee to include "we have inspected the channel's TargetHandle", as Zdra has requested. On modern connection managers this will often be essentially free, by using the TargetID property.