chore: checkpoint before Python removal

vendor/lettre/src/rustls_crypto.rs

@@ -0,0 +1,14 @@
+use std::sync::Arc;
+
+use rustls::crypto::CryptoProvider;
+
+pub(crate) fn crypto_provider() -> Arc<CryptoProvider> {
+    CryptoProvider::get_default().cloned().unwrap_or_else(|| {
+        #[cfg(feature = "aws-lc-rs")]
+        let provider = rustls::crypto::aws_lc_rs::default_provider();
+        #[cfg(not(feature = "aws-lc-rs"))]
+        let provider = rustls::crypto::ring::default_provider();
+
+        Arc::new(provider)
+    })
+}