v0.17.0

This is a significant release and the major breaking changes to be aware of are:

Server backpressure

This release changes the server to be "backpressured" and it mostly concerns subscriptions.
New APIs has been introduced because of that and the API pipe_from_stream has been removed.

Before it was possible to do:

	module
		.register_subscription("sub", "s", "unsub", |_, sink, _| async move {
			let stream = stream_of_integers();

			tokio::spawn(async move {
				sink.pipe_from_stream(stream)
			});
		})
		.unwrap();

After this release one must do something like:

	// This is just a example helper.
	//
	// Other examples:
	// - <https://github.com/paritytech/jsonrpsee/blob/master/examples/examples/ws_pubsub_broadcast.rs>
	// - <https://github.com/paritytech/jsonrpsee/blob/master/examples/examples/ws_pubsub_with_params.rs>
	async fn pipe_from_stream<T: Serialize>(
		pending: PendingSubscriptionSink,
		mut stream: impl Stream<Item = T> + Unpin,
	) -> Result<(), anyhow::Error> {
		let mut sink = pending.accept().await?;

		loop {
			tokio::select! {
				_ = sink.closed() => break Ok(()),

				maybe_item = stream.next() => {
					let Some(item) = match maybe_item else {
						break Ok(()),
					};

					let msg = SubscriptionMessage::from_json(&item)?;

					if let Err(e) = sink.send_timeout(msg, Duration::from_secs(60)).await {
						match e {
							// The subscription or connection was closed.
							SendTimeoutError::Closed(_) => break Ok(()),
							/// The subscription send timeout expired
							/// the message is returned and you could save that message
							/// and retry again later.
							SendTimeoutError::Timeout(_) => break Err(anyhow::anyhow!("Subscription timeout expired")),
						}
					}
				}
			}
		}
	}


	module
		.register_subscription("sub", "s", "unsub", |_, pending, _| async move {
			let stream = stream();
			pipe_from_stream(sink, stream).await
		})
		.unwrap();

Method call return type is more flexible

This release also introduces a trait called IntoResponse which is makes it possible to return custom types and/or error
types instead of enforcing everything to return Result<T, jsonrpsee::core::Error>

This affects the APIs RpcModule::register_method, RpcModule::register_async_method and RpcModule::register_blocking_method
and when these are used in the proc macro API are affected by this change.
Be aware that the client APIs don't support this yet

The IntoResponse trait is already implemented for Result<T, jsonrpsee::core::Error> and for the primitive types

Before it was possible to do:

	// This would return Result<&str, jsonrpsee::core::Error>
	module.register_method("say_hello", |_, _| Ok("lo"))?;

After this release it's possible to do:

	// Note, this method call is infallible and you might not want to return Result.
	module.register_method("say_hello", |_, _| "lo")?;

Subscription API is changed.

jsonrpsee now spawns the subscriptions via tokio::spawn and it's sufficient to provide an async block in register_subscription

Further, the subscription API had an explicit close API for closing subscriptions which was hard to understand and
to get right. This has been removed and everything is handled by the return value/type of the async block instead.

Example:

	module
		.register_subscription::<RpcResult<(), _, _>::("sub", "s", "unsub", |_, pending, _| async move {
			// This just answers the RPC call and if this fails => no close notification is sent out.
			pending.accept().await?;
			// This is sent out as a `close notification/message`.
			Err(anyhow::anyhow!("The subscription failed"))?;
		})
		.unwrap();

The return value in the example above needs to implement IntoSubscriptionCloseResponse and
any value that is returned after that the subscription has been accepted will be treated as a IntoSubscriptionCloseResponse.

Because Result<(), E> is used here the close notification will be sent out as error notification but it's possible to
disable the subscription close response by using () instead of Result<(), E> or implement IntoSubscriptionCloseResponse for other behaviour.

[Added]

• feat(server): configurable limit for batch requests. (#1073)
• feat(http client): add tower middleware (#981)

[Fixed]

• add tests for ErrorObject (#1078)
• fix: tokio v1.27 (#1062)
• fix: remove needless Semaphore::(u32::MAX) (#1051)
• fix server: don't send error on JSON-RPC notifications (#1021)
• fix: add max_log_length APIs and use missing configs (#956)
• fix(rpc module): subscription close bug (#1011)
• fix: customized server error codes (#1004)

[Changed]

• docs: introduce workspace attributes and add keywords (#1077)
• refactor(server): downgrade connection log (#1076)
• chore(deps): update webpki-roots and tls (#1068)
• rpc module: refactor subscriptions to return impl IntoSubscriptionResponse (#1034)
• add IntoResponse trait for method calls (#1057)
• Make jsonrpc protocol version field in Response as Option (#1046)
• server: remove dependency http (#1037)
• chore(deps): update tower-http requirement from 0.3.4 to 0.4.0 (#1033)
• chore(deps): update socket2 requirement from 0.4.7 to 0.5.1 (#1032)
• Update bound type name (#1029)
• rpc module: remove SubscriptionAnswer (#1025)
• make verify_and_insert pub (#1028)
• update MethodKind (#1026)
• remove batch response (#1020)
• remove debug log (#1024)
• client: rename max_notifs_per_subscription to max_buffer_capacity_per_subscription (#1012)
• client: feature gate tls cert store (#994)
• server: bounded channels and backpressure (#962)
• client: use tokio channels (#999)
• chore: update gloo-net ^0.2.6 (#978)
• Custom errors (#977)
• client: distinct APIs to configure max request and response sizes (#967)
• server: replace FutureDriver with tokio::spawn (#1080)
• server: uniform whitespace handling in rpc calls (#1082)