ApolloClient example

[webdeb]

Hi, just saw you PR to fix Apollos InMemoryCache to support custom directives, which landed in the master is part of the actual code base.
I am using ApolloClient and would like to implement a custom directive on the client side.

I would really appreciate, if you could drop in an example here, how you would implement the simplest directive for ApolloClient? Or maybe a hint where to look it up. I found only some ServerSide examples, and I am bit confused about the client side part. Thank you