chore: Refactor package structure

pkg/messages/options.go

@@ -0,0 +1,20 @@
+package messages
+
+type Option struct {
+	Code OptionCode
+	Data []byte
+}
+
+func (o Option) Size() uint8 {
+	if len(o.Data) > 0 {
+		return uint8(o.Data[0])
+	}
+	return 0
+}
+
+type Options map[OptionCode]Option
+
+func (opts Options) HasOption(code OptionCode) bool {
+	_, exists := opts[code]
+	return exists
+}