The intent of this commit is to remove the quantity of log that is being pushed to user.

This commit removes the redeclaration of a set up tracing methods to centralise
the tokio-tracing subscriber within the extension crate. It also add the
feature to filter information based on Environment variable.
This makes it possible to define the log level for tokio tracing like
this:
```
RUST_LOG=debug dora-daemon --run-dataflow dataflow.yml
```

I have also unified the feature flag to make it easier to manage tracing features among the workspace.

I did not change the default behaviour of tracing in our crates and therefore by
using the command above you should get the same tracing log as before.

fix merge conflict generated

Don't send replies for `SendMessage` requests when using TCP

Allows queueing of multiple messages on the TCP socket, which considerably improves throughput.

Sends a list of all queued events in the reply instead of sending them one-by-one. This way, we avoid some communication overhead.

We currently need an additional request to prepare zero-copy shared memory messages. For small messages, it might be faster to avoid this extra round-trip and send the message directly over TCP. This commit implements support for this. Messages smaller than a threshold (currently set to 4096 bytes) are sent via TCP, while larger messages still use shared memory.

This step also enables future optimizations such as queueing output messages in order to improve the throughput.

The cxx crate is able to invoke the Rust destructors from C++

Without joining the thread it is killed suddenly by the OS when the executable exits. This causes interrupted connections to the daemon, which leads to some errors in the log messages. This commit fixes this by joining the event stream thread again, with the following improvements:

- Instead of joining the thread directly on drop, we now do the joining in a second thread and report the join result over a channel. This allows us to use a timeout when waiting for the join result in the drop implementation, so that we don't block indefinitely.
- We now share the ownership of the join handle between the node and the event stream. This way, its drop handler is only run after both instances were dropped. This way we avoid the deadlock that happened when joining the event steam thread before the event stream instance was dropped.

Avoids the need to catch the thread's panics.

It is not guaranteed that the `EventStream` is dropped before the `DoraNode`. If it is dropped later on the same thread, this `join` leads to a deadlock.

Since inputs are passed through borrowed shared memory, we need to report back when we're done with them. We do this through a drop handler. By using a rendezvous channel for forwarding, we avoid that the drop handler is stuck in the queue if the node finished already.

Bumps [tokio](https://github.com/tokio-rs/tokio) from 1.23.1 to 1.24.2.
- [Release notes](https://github.com/tokio-rs/tokio/releases)
- [Commits](https://github.com/tokio-rs/tokio/commits)

---
updated-dependencies:
- dependency-name: tokio
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

We cannot wait until all operators of the runtime node are finished because operators might be subscribed to other operators.

To allow for individual testing and benchmarking. This will also enable reuse of the library in other projects.

To prepare for future feature, this commit initiate a `__init__.py` file
that makes the dora python node api, a mixed python/rust project.

Any python function or variable included in the `__init__.py` will be
distributed along rust function declared in `src/lib.rs`.

https://github.com/dora-rs/dora/issues/163 has shown the limitation on
depending too much on `pyo3`.

Bumps [tokio](https://github.com/tokio-rs/tokio) from 1.21.2 to 1.23.1.
- [Release notes](https://github.com/tokio-rs/tokio/releases)
- [Commits](https://github.com/tokio-rs/tokio/compare/tokio-1.21.2...tokio-1.23.1)

---
updated-dependencies:
- dependency-name: tokio
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

The goal is to avoid the latency of the TCP socket.

Co-authored-by: Haixuan Xavier Tao <tao.xavier@outlook.com>