• Rename Connector::{ssl => openssl}. #2503
• Improve Client instantiation efficiency when using openssl by only building connectors once. #2503
• ClientRequest::send_body now takes an impl MessageBody. #2546
• Rename MessageBody => ResponseBody to avoid conflicts with MessageBody trait. #2546
• impl Future for ResponseBody no longer requires the body type be Unpin. #2546
• impl Future for JsonBody no longer requires the body type be Unpin. #2546
• impl Stream for ClientResponse no longer requires the body type be Unpin. #2546