Update README for examples

Examples/Echo/README.md

@@ -1,20 +1,17 @@
-This directory contains a simple echo server that can be used to
-verify interoperability of Swift and Go gRPC servers.
+# Echo, a gRPC Sample App
 
-The Go directory contains a Go client and server. The server
+This directory contains a simple echo server and client
+that demonstrates all four gRPC API styles (Unary, Server 
+Streaming, Client Streaming, and Bidirectional Streaming) 
+and to verify interoperability of Swift and Go gRPC clients
+and servers.
+
+The [Go](Go) directory contains a Go client and server. The server
 listens on localhost:8080 and the client connects to this by
 default but can be pointed at other servers using the "-a" 
 command-line option.
 
-The Swift directory contains a Mac app that contains a Swift
-client and server. The server starts with the app and listens
-on localhost:8081. The client runs in a window and connects by
-default to this port but can be pointed at other servers using
-the address field in the Echo window.
-
-When the Go server and Mac app are running on the same machine,
-both clients can be used to connect to both servers.
-
-Also, for comparison, the Objective-C directory contains an iOS
-client that connects to gRPC echo servers.
+The [Swift](Swift) directory contains a Mac app and a command-line tool
+that can be built with the Swift Package Manager. Both contain
+a Swift client and server. 
 

Examples/README.md

@@ -1,6 +1,24 @@
 
 # Examples
 
-Start with the Echo sample. It demonstrates a simple echo service with nonstreaming and streaming
-APIS and that can be run with or without TLS. Swift clients and servers are built in a Mac app, 
-and an interoperable client and server is in the Go directory.
+## Swift gRPC generated code examples
+
+[Echo](Echo)
+This sample demonstrates a simple echo service with nonstreaming and streaming APIS.
+It can be run with or without TLS. Swift clients and servers are built in a Mac app 
+and in a command-line tool that is built with the Swift Package Manager. An 
+interoperable client and server is in the [Echo/Go] directory. 
+
+This sample uses a client and server interface generated by the Swift gRPC plugin
+for protoc.
+
+## Low-level demonstrations
+
+[Simple](Simple)
+This is a simple command line tool, built with the Swift Package Manager, that 
+implements a simple client and server using low-level gRPC APIs.
+
+[Sessions](Sessions)
+This is a Mac app that also implements a simple client and server using low-level
+gRPC APIs.
+