Middleware for metrics (#576)

* Squashed MethodSink

* Middleware WIP

* Passing all the information through

* Unnecessary `false`

* Apply suggestions from code review

Co-authored-by: David <[email protected]>

* Add a setter for middleware (#577)

* Fix try-build tests

* Add a middleware setter and an example

* Actually add the example

* Grumbles

* Use an atomic

* Set middleware with a constructor instead

* Resolve a todo

* Update ws-server/src/server.rs

Co-authored-by: Maciej Hirsz <[email protected]>

* Update ws-server/src/server.rs

Co-authored-by: Maciej Hirsz <[email protected]>

* Update ws-server/src/server.rs

Co-authored-by: Maciej Hirsz <[email protected]>

Co-authored-by: Maciej Hirsz <[email protected]>

* Middleware::on_response for batches

* Middleware in HTTP

* fmt

* Server builder for HTTP

* Use actual time in the example

* HTTP example

* Middleware to capture method not found calls

* An example of adding multiple middlewares. (#581)

* Add an example of adding multiple middlewares.

* Update examples/multi-middleware.rs

Co-authored-by: Maciej Hirsz <[email protected]>

* Update examples/Cargo.toml

Co-authored-by: Maciej Hirsz <[email protected]>

Co-authored-by: Maciej Hirsz <[email protected]>

* Move `Middleware` to jsonrpsee-types (#582)

* Move `Middleware` to jsonrpsee-types

* Move Middleware trait to jsonrpsee-types

* Add some docs.

* Link middleware to `with_middleware` methods in docs

* Doctests

* Doc comment fixed

* Clean up a TODO

* Switch back to `set_middleware`

* fmt

* Tests

* Add `on_connect` and `on_disconnect`

* Add note to future selves

Co-authored-by: David <[email protected]>