postEncode expect all values to be strings

[Fox32]

The sendTiming parameter time is of type int, but internally type string is required. Im using

      _analytics.sendTiming('LoadTime', stopwatch.elapsedMilliseconds);

but it crashes as postEncode in usage_impl.dart requires all map values to be strings, but 'utt' is an integer. Therefore time should be converted to a string first.

[Fox32]

I think in the end that would also mean that setSessionValue and sendEvent should do that, too?

[devoncarew]

Awesome, good catch! lgtm. Can you add yourself to the end of the AUTHORS file as well? It should be a

First Last <email>

format. Thanks!

[Fox32]

Done

[devoncarew]

Great, thanks!

[devoncarew]

(pushed a new version to capture this fix)