reverse_resolve_async

Asynchronously gets the result of a reverse geocoding query using the backend.

Typically, a single result will be returned representing the place at a given latitude and longitude (the `lat` and `lon` keys to params ); but in some cases the results will be ambiguous and *multiple* results will be returned. They will be returned in order of relevance, with the most relevant result first in the list.

The params hash table is in the format used by Telepathy, and documented in the [Telepathy specification](http://telepathy.freedesktop.org/spec/Connection_Interface_Location.html#Mapping:Location).

See also: [XEP-0080 specification](http://xmpp.org/extensions/xep-0080.html).

Use reverse_resolve to do the same thing synchronously.

When the operation is finished, callback will be called. You can then call reverse_resolve_async.end to get the result of the operation.

Parameters:

this	a Backend.
cancellable	optional Cancellable object, null to ignore.
callback	a TaskReadyCallback to call when the request is satisfied.
params	a GenericSet with string keys, and Value values.
user_data	the data to pass to callback function.