StreamableHttp -- resumability support for servers (#587)

examples/servers/simple-streamablehttp/README.md

@@ -9,6 +9,7 @@ A simple MCP server example demonstrating the StreamableHttp transport, which en
 - Task management with anyio task groups
 - Ability to send multiple notifications over time to the client
 - Proper resource cleanup and lifespan management
+- Resumability support via InMemoryEventStore
 
 ## Usage
 
@@ -32,6 +33,23 @@ The server exposes a tool named "start-notification-stream" that accepts three a
 - `count`: Number of notifications to send (e.g., 5)
 - `caller`: Identifier string for the caller
 
+## Resumability Support
+
+This server includes resumability support through the InMemoryEventStore. This enables clients to:
+
+- Reconnect to the server after a disconnection
+- Resume event streaming from where they left off using the Last-Event-ID header
+
+
+The server will:
+- Generate unique event IDs for each SSE message
+- Store events in memory for later replay
+- Replay missed events when a client reconnects with a Last-Event-ID header
+
+Note: The InMemoryEventStore is designed for demonstration purposes only. For production use, consider implementing a persistent storage solution.
+
+
+
 ## Client
 
-You can connect to this server using an HTTP client, for now only Typescript SDK has streamable HTTP client examples or you can use (Inspector)[https://github.com/modelcontextprotocol/inspector]
+You can connect to this server using an HTTP client, for now only Typescript SDK has streamable HTTP client examples or you can use [Inspector](https://github.com/modelcontextprotocol/inspector)