public var hasPendingWrites:Boolean
Returns true if the snapshot contains the result of local writes (e.g. set() or update() calls)
that have not yet been committed to the backend. If your listener has opted into metadata updates
you will receive another snapshot with hasPendingWrites
equal to NO once the writes have
been committed to the backend.
public var isFromCache:Boolean
Returns true if the snapshot was created from cached data rather than guaranteed up-to-date server
data. If your listener has opted into metadata updates you will receive another snapshot
with isFromCache
equal to NO once
the client has received up-to-date data from the backend.