'WiredHeadset' event not working on iOS

I'm using the below pattern (1.) per the docs, but the 'WiredHeadset' event doesn't seem to be firing on iOS. I also tried with NativeEventEmitter (doing this by using NativeModules to get the InCallManager then wrapping it in NativeEventEmitter, see 2.). I'm on version 0.53 of RN.

import { DeviceEventEmitter } from 'react-native';

DeviceEventEmitter.addListener('WiredHeadset', function (data) {
    // --- do something with events
});

const InCallManagerEvent = new NativeEventEmitter(NativeModules.InCallManager)

Start by reproducing the documented DeviceEventEmitter pattern on iOS with React Native 0.53, then compare it with the NativeEventEmitter(NativeModules.InCallManager) setup described in the issue. Trace the WiredHeadset event entry point and verify that a connected or disconnected wired headset produces the documented event on iOS.