[BUG] - Async TLS example fails to compile

Description

The async example in README fails to compile, specifically the line:

let mut ftp_stream = ftp_stream.into_secure(AsyncNativeTlsConnector::from(TlsConnector::new()), "test.rebex.net").await.unwrap();

Error message:

error[E0271]: type mismatch resolving `<AsyncNativeTlsConnector as AsyncTlsConnector>::Stream == AsyncNoTlsStream`
   --> test/src/main.rs:8:49
    |
8   | ...am.into_secure(AsyncNativeTlsConnector::from(TlsConnector::new()), "...
    |       ----------- ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `AsyncNoTlsStream`, found `AsyncNativeTlsStream`
    |       |
    |       required by a bound introduced by this call
    |
note: required by a bound in `ImplAsyncFtpStream::<T>::into_secure`
   --> /home/michaelyang/.cargo/registry/src/index.crates.io-6f17d22bba15001f/suppaftp-5.1.2/src/async_ftp/mod.rs:122:47
    |
122 | ... AsyncTlsConnector<Stream = T> + 'static,
    |                       ^^^^^^^^^^ required by this bound in `ImplAsyncFtpStream::<T>::into_secure`

Investigation

I did some digging around in the source file, and it appears that the problem stems from the fact that ImplAsyncFtpStream::into_secure requires the bound on T for the parameter tls_connector:

tls_connector: impl AsyncTlsConnector<Stream = T> + 'static

which suggests that the stream before and after switching to secure mode must be the same, and hence why AsyncFtpStream with T = AsyncNoTlsStream failed to be promoted to a secure ftp stream with T = AsyncNativeTlsStream.

On the other hand, the into_secure documentation provides the correct example:

let mut ctx = TlsConnector::new();
let mut ftp_stream = ImplAsyncFtpStream::connect("127.0.0.1:21").await.unwrap();
let mut ftp_stream = ftp_stream.into_secure(ctx, "localhost").await.unwrap();

Where the original ftp_stream has an indeterminate generic type T that is subsequently inferred in the following line.

Hence, which of the two (either promotion from insecure stream or direct construction from ImplAsyncFtpStream) examples is the desired behaviour?

Environment

OS: Linux 6.2.6
Architecture x86_64
Rust version 1.70.0
library version 5.1.2

veeso / suppaftp