Use TryFrom trait for producers and consumers

[JanKaul]

Hi, this is just a question to get more clarity on the structure of this crate.

If I'm not mistaken this crate shares some similarities with the datafusion-proto crate. The datafusion-proto crate extensively uses the From trait for the conversion between the native datafusion representation and the protobuf representation.

I was wondering why the current implementation for datafusion-substrait uses a different approach? I thought it might be beneficial if both crates share a similar structure. Since the conversion to substrait might impose certain errors, the From trait might not be applicable but the TryFrom trait could still be used.

The current implementation uses async functions for the conversion from substrait to datafusion. Might this be the reason. However, I don't see why the async functions are currently necessary.

Thanks for the help.