feat: export AbstractRPCPlugin and related types from RPCPlugin

src/index.ts

@@ -12,6 +12,9 @@ export { SocketConnection } from "./core/SocketConnection";
 export { SocketServer } from "./core/SocketServer";
 export { EventEmitter } from "./utils/EventEmitter";
 
+export { AbstractRPCPlugin, createHookRunner } from './core/RPCPlugin';
+export type { RPCPlugin, RPCPluginHooks, RPCPluginHooksCtx } from './core/RPCPlugin';
+
 export { injectSocketClient } from "./core/SocketClient";
 export { injectSocketServer } from "./core/SocketServer";
 import { injectSocketIOImplements } from "./implements/socket.io";