A container that holds a log request and provides an iterator to read logs.
A _LogQueryResult object is the standard returned item for a call to fetch().
It is iterable - each value returned is a log that the user has queried for,
and internally, it holds a cursor that it uses to fetch more results once the
current, locally held set, are exhausted.
Properties:
_request: A LogReadRequest that contains the parameters the user has set for
the initial fetch call, which will be updated with a more current cursor
if more logs are requested.
_logs: A list of RequestLogs corresponding to logs the user has asked for.
_read_called: A boolean that indicates if a Read call has even been made
with the request stored in this object.