Adds apiserver proxy doc.go

staging/src/k8s.io/apiserver/pkg/util/proxy/doc.go

@@ -0,0 +1,36 @@
+/*
+Copyright 2024 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// Among other files, this directory contains functionality for two
+// stream proxies: streamtranslator.go and streamtunnel.go. Both of
+// these proxies allow the inter-connection of WebSocket and SPDY
+// streaming connections.
+//
+// The stream translator proxy is used for the RemoteCommand
+// subprotocol (e.g. kubectl exec, cp, and attach), and it connects
+// the output streams of a WebSocket connection (e.g. STDIN, STDOUT,
+// STDERR, TTY resize, and error streams) to the input streams of a
+// SPDY connection.
+//
+// The stream tunnel proxy tunnels SPDY frames through a WebSocket
+// connection, and it is used for the PortForward subprotocol (e.g.
+// kubectl port-forward). This proxy implements tunneling by transparently
+// encoding and decoding SPDY framed data into and out of the payload of a
+// WebSocket data frame. The primary structure for this tunneling is
+// the TunnelingConnection. A lot of the other code in streamtunnel.go
+// is for properly upgrading both the upstream SPDY connection and the
+// downstream WebSocket connection before streaming begins.
+package proxy // import "k8s.io/apiserver/pkg/util/proxy"