Improve documentation on simulateDataStall

Explain that:
 - The method does not cause an actual data stall.
 - The detectionMethod parameter refers to
   ConnectivityDiagnosticsManager.DataStallReport constants (which
   already use an IntDef).
 - timestampMillis is relative to SystemClock.elapsedRealtime.

Fixes: 183972768
Test: m
Change-Id: I2eeb79e0e8ec6e8fd3b8fe1dcb1abbf2e6338983
1 file changed
tree: 1bfefb1f83612005e490c6cf2cd9ecf5df8bdf02
  1. core/
  2. framework/
  3. service/
  4. services/
  5. tests/
  6. OWNERS
  7. TEST_MAPPING