Fixed LoRa-Shield recv invalid #39

Job	Run time
build (examples/UnitTestExample)	1m 3s
build (examples/ETHOTA)	57s
build (examples/HelloServer)	59s
build (examples/SDWebServer)	54s
build (examples/MQTTClient)	55s
build (examples/ESPMQTTSClient)	51s
build (examples/StaticIPAddress)	50s
build (examples/UDPClientReceiver)	58s
build (examples/UDPClientSender)	54s
build (examples/UDPClientReceiverDirectPC)	1m 9s
build (examples/UDPClientSenderDirectPC)	54s
build (examples/AsyncUDPServer)	56s
build (examples/AsyncUDPClient)	58s
build (examples/WebSocketClient)	57s
build (examples/WebSocketServer)	1m 5s
build (examples/TCPClient)	56s
build (examples/TCPServer)	57s
build (examples/InternetComTest)	55s
	17m 8s

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