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

sketch/decoder_manager.h

@@ -0,0 +1,70 @@
+/*
+    This file is part of the Arduino_RPClite library.
+
+    Copyright (C) Arduino s.r.l. and/or its affiliated companies
+
+    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/.
+    
+*/
+
+// This is a static implementation of the decoder manager
+
+#ifndef RPCLITE_DECODER_MANAGER_H
+#define RPCLITE_DECODER_MANAGER_H
+
+#include <array>
+#include "transport.h"
+#include "decoder.h"
+
+class RpcDecoderManager {
+
+public:
+
+    RpcDecoderManager(const RpcDecoderManager&) = delete;
+    RpcDecoderManager& operator=(const RpcDecoderManager&) = delete;
+
+    RpcDecoder<>* getDecoder(ITransport& transport) {
+        for (auto& entry : decoders_) {
+            if (entry.transport == &transport) {
+                return entry.decoder;
+            }
+
+            if (entry.transport == nullptr) {
+                entry.transport = &transport;
+                entry.decoder = new RpcDecoder<>(transport);
+
+                decoders_count++;
+                return entry.decoder;
+            }
+        }
+
+        return nullptr;
+    }
+
+    size_t getDecodersCount() const {
+        return decoders_count;
+    }
+
+    static RpcDecoderManager& getInstance() {
+        static RpcDecoderManager instance; // thread-safe in C++11+
+        return instance;
+    }
+
+private:
+
+    RpcDecoderManager(){};
+
+    static RpcDecoderManager* instance;
+
+    struct Entry {
+        ITransport* transport = nullptr;
+        RpcDecoder<>* decoder = nullptr;
+    };
+
+    std::array<Entry, RPCLITE_MAX_TRANSPORTS> decoders_;
+    size_t decoders_count{0};
+};
+
+#endif //RPCLITE_DECODER_MANAGER_H