v2.1.55

• Add static JsonRpc.Attach<T>(IJsonRpcMessageHandler) overloads #251
• Avoid transmitting an async Task result as an empty object back to the client #259
• Dynamic client proxies always implement IDisposable #298
• Dynamic client proxies always expose original JsonRpc instance via the new IJsonRpcClientProxy interface #295 #300
• Accept a response where the id is encoded as a string instead of a number #291