Expo's location distanceInterval does not seem to be respected

[elidourado]

We are currently using Expo's Location.watchPositionAsync function to monitor for location changes. We are passing {distanceInterval: 2000} as an option that is supposed to limit updates to when the phone has moved at least 2000 meters. However, updates are much more frequent.

Concerns:

• More frequent updates could impact device battery life.
• On-device geocoding, which we are currently using, is a scarce resource. If we call it too often, this could cause problems. Right now we are manually rate-limiting to at most every two minutes.

If we can't find a fix using the Expo library, we may have to move to native code to handle this issue.

[elidourado]

Note that we are not actually receiving background location yet. We will need to switch to the Location.startLocationUpdatesAsync function when we are ready to do that. So for the time being, there should be no hit to battery life.

[elidourado]

On iOS we'll use Core Location's startMonitoringSignificantLocationChanges(). On Android we can use LocationRequest.Builder's setMinUpdateDistanceMeters and setMinUpdateIntervalMillis methods, setting minimum distance to 500m and minimum update time to 5 minutes. That should create identical behavior on both platforms.

[elidourado]

Closing this for now since we are using native code on iOS and not testing on Android yet. Should be a one-file fix later when we want to support a native implementation on Android.