fix: make router socket non-blocking to prevent poll loop stalls

sketch/dispatcher.h

@@ -0,0 +1,76 @@
+/*
+    This file is part of the Arduino_RPClite library.
+
+    Copyright (c) 2025 Arduino SA
+
+    This Source Code Form is subject to the terms of the Mozilla Public
+    License, v. 2.0. If a copy of the MPL was not distributed with this
+    file, You can obtain one at http://mozilla.org/MPL/2.0/.
+    
+*/
+
+#ifndef RPCLITE_DISPATCHER_H
+#define RPCLITE_DISPATCHER_H
+
+#include "wrapper.h"
+#include "error.h"
+
+struct DispatchEntry {
+    MsgPack::str_t name;
+    MsgPack::str_t tag;
+    IFunctionWrapper* fn;
+};
+
+template<size_t N>
+class RpcFunctionDispatcher {
+public:
+
+    RpcFunctionDispatcher() = default;
+
+    template<typename F>
+    bool bind(MsgPack::str_t name, F&& f, MsgPack::str_t tag="") {
+        if (_count >= N) return false;
+
+        if (isBound(name)) return false;
+
+        _entries[_count++] = {name, tag, wrap(std::forward<F>(f))};
+        return true;
+    }
+
+    bool isBound(const MsgPack::str_t& name) const {
+        for (size_t i = 0; i < _count; ++i) {
+            if (_entries[i].name == name) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    bool hasTag(const MsgPack::str_t& name, MsgPack::str_t& tag) const {
+        for (size_t i = 0; i < _count; ++i) {
+            if (_entries[i].name == name && _entries[i].tag == tag) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    bool call(const MsgPack::str_t& name, MsgPack::Unpacker& unpacker, MsgPack::Packer& packer) {
+        for (size_t i = 0; i < _count; ++i) {
+            if (_entries[i].name == name) {
+                return (*_entries[i].fn)(unpacker, packer);
+            }
+        }
+
+        // handler not found
+        MsgPack::object::nil_t nil;
+        packer.serialize(RpcError(FUNCTION_NOT_FOUND_ERR, name), nil);
+        return false;
+    }
+
+private:
+    DispatchEntry _entries[N];
+    size_t _count = 0;
+};
+
+#endif