implement packet parser

src/packet.js

@@ -0,0 +1,22 @@
+import BufferReader from "./buffer_reader.js";
+
+class Packet {
+
+    constructor(header, path, payload) {
+        this.header = header;
+        this.path = path;
+        this.payload = payload;
+    }
+
+    static fromBytes(bytes) {
+        const bufferReader = new BufferReader(bytes);
+        const header = bufferReader.readByte();
+        const pathLen = bufferReader.readInt8();
+        const path = bufferReader.readBytes(pathLen);
+        const payload = bufferReader.readRemainingBytes();
+        return new Packet(header, path, payload);
+    }
+
+}
+
+export default Packet;