Proposal: A shared trait for tls acceptors that are implemented by both async-tls and async-native-tls

I have some code that implements this using wrapper types, but would really love for a trait like this to exist:

A proposed async-tls-acceptor crate that publishes this trait:

```rust
#[async_trait]
pub trait Acceptor: Clone + Send + Sync + 'static
where
Input: AsyncRead + AsyncWrite + Send + Sync + Unpin + 'static,
{
type Output: AsyncRead + AsyncWrite + Send + Sync + Unpin + 'static;
type Error: std::fmt::Debug + Send + Sync;

async fn accept(&self, input: Input) -> Result;
}
```

The implementation for async-native-tls would be:
```rust
#[async_trait]
impl Acceptor for async_native_tls::TlsAcceptor
where
Input: AsyncRead + AsyncWrite + Send + Sync + Unpin + 'static,
{
type Output = async_native_tls::TlsStream;
type Error = async_native_tls::Error;
async fn accept(&self, input: Input) -> Result {
async_native_tls::TlsAcceptor::accept(&self, input).await
}
}
```

Would this be welcomed?

refs: https://github.com/async-rs/async-tls/issues/43

Start by reviewing the proposed Acceptor trait and the async-tls issue referenced in the body, then compare the async-native-tls TlsAcceptor implementation with async-tls. Determine whether a shared crate and trait fit the project's direction; done would require an accepted design and corresponding implementations, but no project files or tests are named.

Written by the indexing model from the issue text.