[PATCH 0/5] MR8685: wintypes: Implement IMap::{Lookup, HasKey, Insert} for IPropertySet.

[Vibhav Pant (＠vibhavp)]

`IMap` is implemented on top of a `rb_tree` guarded with an `SRWLOCK`. We need the map to be thread safe as:

* `PropertySet` is marked as `IAgileObject`.
* I plan to use `PropertySet` as the backing store for [`DeviceInformation::Properties`](https://learn.microsoft.com/en-us/uwp/api/windows.devices.enumeration.device...). These properties can be updated by apps after receiving an [`Updated`](https://learn.microsoft.com/en-us/uwp/api/windows.devices.enumeration.device...) event from the device watcher with [`DeviceInformation::Update`](https://learn.microsoft.com/en-us/uwp/api/windows.devices.enumeration.device...). The current `DeviceWatcher` implementation dispatches the event delegates for `Update` from a separate thread.