chore(implementation)!: use Jetty-12 core without servlets

Port the invoker to upgrade to Eclipse Jetty-12 version 12.  Specifically using the new core APIs of Eclipse Jetty-12 that allow the overhead of a Servlet container to be avoided.

BREAKING CHANGE: use Java 17 or above, as required by Eclipse Jetty-12.

Signed-off-by: Lachlan Roberts <[email protected]>

Author: lachlan-roberts

invoker/core/src/main/java/com/google/cloud/functions/invoker/http/HttpResponseImpl.java

@@ -96,7 +96,23 @@ public OutputStream getOutputStream() {
               false,
               outputBufferSize / 2,
               outputBufferSize);
-      outputStream = new ContentSinkOutputStream(bufferedContentSink);
+
+      // TODO: remove override of close() when changes from
+      //    https://github.com/jetty/jetty.project/pull/13972 are released.
+      outputStream =
+          new ContentSinkOutputStream(bufferedContentSink) {
+            boolean closed = false;
+
+            @Override
+            public void close(Callback callback) throws IOException {
+              if (closed) {
+                callback.succeeded();
+              }
+
+              closed = true;
+              super.close(callback);
+            }
+          };
     }
     return outputStream;
   }