[Telepathy] improvements to avatar and aliasing interfaces

[Robert McQueen]

Abner Jose wrote:
> What about aliasing? Will it work in the same way as Avatar?

It's a different problem to avatars because often aliases are pushed to
you, and it's not often it requires a round-trip to the server. The idea
I had for aliasing was that we could leave the existing API as-is, with
RequestAliases, but also add a function GetAliases, which would return
the current known value of any cached/received/heuristically-determined
aliases, but also potentially sending off some longer-running requests
which would return AliasChanged later.

On a similar note, I was considering an API on the Connection, something
like ContactQuery, or the turbo-handle inspector, which would take a
load of handles and return you a sparse dictionary for each, containing
any information known about them keyed by identifiers, eg 1 could be
string value of the handle, 2 could be the alias, 3 could be the
presence, 4 could be the avatar token, 5 could be the handle owner (if
the given handle was channel specific).

Also, the return value could include opportunistic results about any
owner handles (in the same way that DNS queries can return extra
relevant results). It could also have the semantic of sending off any
relevant long-running queries, and later emitting signals when this
information was received.

The intention would be to reduce bus-roundtrips (which are the real
performance killer) when e.g. joining a channel, or receiving an
invitation from someone, etc: rather than querying 3 or 4 different
methods for handle x y and z, you can immediately make 1 method call for
[xyz] and scrape out any info the connection manager has about them at
the moment, and hook the signals for any subsequent updates.

Any thoughts?

> BR.

Regards,
Rob