This provides a clear and consistent interface for selecting TLS-related
features on both (xmpp and tokio-xmpp) crates. All feature checks have
been revamped. All working combinations have been tested (including a
connectivity test + --all-features docs build) using:
```
set -xeuo pipefail
features=(aws_lc_rs ring ktls,aws_lc_rs ktls,ring aws_lc_rs,ring aws_lc_rs,ring,ktls native-tls rustls-any-backend)
export RUSTFLAGS=" -D warnings"
cargo test --no-default-features
cargo test
for feature in ${features[@]}; do
echo ">>> BUILDING with $feature" 2>&1
# Running code or building examples cannot succeed with rustls-any-backend.
features="starttls,$feature"
if [ "$feature" != 'rustls-any-backend' ]; then
if ! cargo test --no-default-features --features="$features"; then
echo ">>> BUILD FAILED for tls feature set: $features" >&2
exit 1
fi
set +e
timeout -sINT -p -k 2 3 cargo run --no-default-features --features="$features" --example keep_connection -- test@hub.sotecware.net "$(pass xmpp/test@hub.sotecware.net)"
status="$?"
set -e
if [ $status -ne 0 ]; then
echo ">>> keep_connection did not shut down cleanly! (status: $status)" >&2
exit 1
fi
else
if ! cargo build --no-default-features --features="$feature"; then
echo ">>> BUILD FAILED for tls feature set: $features" >&2
exit 1
fi
fi
done
RUSTDOCFLAGS="--cfg docsrs" RUSTFLAGS="--cfg xmpprs_doc_build" cargo +nightly doc -Zrustdoc-map --all-features
```
This allows to detect and handle dying streams without getting stuck
forever.
Timeouts are always wrong, though, so we put the burden of choosing the
right values (mostly) on the creator of a stream.
