Event Subscription for Query/Mutation execution #873

I'd like to subscribe to a set of events which are called before and after each query/mutation is executed within an operation, so I can trace, monitor and measure the performance of each query/mutation within my schema. I've looked through and can't see how I'd achieve this.

Right now I'm subscribing to Events::POST_EXECUTOR which allows me to log the duration of the complete GQL operation, though operation names are set by the client so aren't really suited for this purpose, especially if two clients use the same operation name to perform a different interaction.