Flush extra bytes

src/Agilent4uhv.cpp

@@ -1582,6 +1582,11 @@ void Agilent4uhv::receive_message(vector<unsigned char> &payload)
 	Serial2Client::read_until(ETX, message);
 	Serial2Client::read(CRC_LENGTH, crc);
 	assert(Serial2Client::input_length() == 0);
+	int ilen = Serial2Client::input_length();
+	if (ilen > 0) {
+		vector<unsigned char> discard;
+		Serial2Client::read(ilen, discard);
+	}
 
 	message.insert(message.end(), crc.begin(), crc.end());