Document multiple client proxy patterns

[AArnott]

Summary

Users often attempt to call static JsonRpc.Attach<T> multiple times on the same stream to create multiple client proxies. This is a common mistake that leads to failures because each static call creates a distinct JsonRpc instance, and multiple instances cannot safely share one transport.

Changes

This PR documents the three supported patterns for constructing multiple client proxies over a single JSON-RPC connection, with working code examples:

1. Create one proxy implementing multiple interfaces at once

   • Single proxy object implementing multiple RPC interface contracts
   • Simplest option when the set of interfaces is known upfront

2. Create JsonRpc first, then call instance Attach<T> multiple times

   • Most flexible pattern for creating proxies incrementally
   • Clear separation between transport setup and proxy creation

3. Extract JsonRpc from the first proxy using IJsonRpcClientProxy

   • Useful when starting with a static proxy attachment
   • Shows the relationship between proxies and the underlying connection

Files Changed

• docfx/docs/proxies.md: Added new "Multiple proxies on one connection" section with clear guidance and code references for each pattern
• samples/Proxies.cs: Added working code examples for all three patterns with dedicated #region markers for documentation

All samples compile and pass tests.

[Copilot]

Pull request overview

This PR adds documentation and sample code showing the supported ways to create multiple strongly-typed client proxies over a single StreamJsonRpc connection, avoiding the common mistake of calling static JsonRpc.Attach<T> multiple times on the same stream.

Changes:

• Added a new “Multiple proxies on one connection” section to the proxies documentation with guidance and snippet references.
• Added sample code regions demonstrating three supported multi-proxy patterns (multi-interface proxy, multiple instance Attach<T> calls, and extracting JsonRpc from an existing proxy).

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
docfx/docs/proxies.md	Documents the supported multi-proxy patterns and links to corresponding sample snippets.
samples/Proxies.cs	Provides the code examples (with #region markers) used by the documentation.