Add async_property

[ryananguiano]

What is this project?

You can use @async_property just as you would with @property, but on an async function.

class Foo:
    @async_property
    async def remote_value(self):
        return await get_remote_value()

The property remote_value now returns an awaitable coroutine.

instance = Foo()
await instance.remote_value

Why is it awesome?

• Both regular and cached property.
• Cached properties can be accessed multiple times without repeating function.
• Cus duh!

[ryananguiano]

Forgot the link: https://github.com/ryananguiano/async_property

[ryananguiano]

Ready for merge