HTTP/2: graceful shutdown of active connections (closes #1106). Previously, while shutting down gracefully, the HTTP/2 connections were closed in transition to idle state after all active streams have been processed. That might never happen if the client continued opening new streams. Now, nginx sends GOAWAY to all HTTP/2 connections and ignores further attempts to open new streams. A worker process will quit as soon as processing of already opened streams is finished.

--- a/src/http/v2/ngx_http_v2.h
+++ b/src/http/v2/ngx_http_v2.h
@@ -146,6 +146,7 @@ struct ngx_http_v2_connection_s {
     unsigned                         closed_nodes:8;
     unsigned                         settings_ack:1;
     unsigned                         blocked:1;
+    unsigned                         goaway:1;
 };