Changes with nginx 1.19.9 30 Mar 2021
*) Bugfix: nginx could not be built with the mail proxy module, but without the ngx_mail_ssl_module; the bug had appeared in 1.19.8.
*) Bugfix: "upstream sent response body larger than indicated content length" errors might occur when working with gRPC backends; the bug had appeared in 1.19.1.
*) Bugfix: nginx might not close a connection till keepalive timeout expiration if the connection was closed by the client while discarding the request body.
*) Bugfix: nginx might not detect that a connection was already closed by the client when waiting for auth_delay or limit_req delay, or when working with backends.
*) Bugfix: in the eventport method.