@Override
	public void log(@LogPriority final int priority, @StringRes final int messageRes,
					@Nullable final Object... params) {
		final String message = context.getString(messageRes, params);
		log(priority, message);
	}
Returns the last received value of Battery Level characteristic, or -1 if such
does not exist, hasn't been read or notification wasn't received yet.
<p>
The value returned will be invalid if overridden {@link #readBatteryLevel()} and
{@link #enableBatteryLevelNotifications()} were used.

@return The last battery level value in percent.
@deprecated Keep the battery level in your manager instead.
ble/src/main/java/no/nordicsemi/android/ble/BleManager.java