Implement a feature support check for clients to allow pre-emptively querying for supported methods

[danegsta]

We should consider adding support for clients to pre-emptively check if a client supports a given method rather than depending on not supported exceptions as we may need/want to pre-emptively enable or disable UI/features based on what the user's selected client supports.

[bwateratmsft]

Can we use Decorators for this in some capacity? e.g. a utility method to see if a function on an object has an "ICantDoThatDave" decorator.

[danegsta]

There hasn't been a JavaScript project I've worked on where I haven't eventually gone mad with power and used decorators for metaprogramming, so I'm fully on board with this idea.