Implemented flush for Serial UART API

platforms/nuttx/src/px4/common/SerialImpl.cpp

@@ -309,6 +309,13 @@ ssize_t SerialImpl::write(const void *buffer, size_t buffer_size)
 	return written;
 }
 
+void SerialImpl::flush()
+{
+	if (_open) {
+		tcflush(_serial_fd, TCIOFLUSH);
+	}
+}
+
 const char *SerialImpl::getPort() const
 {
 	return _port;

platforms/nuttx/src/px4/common/include/SerialImpl.hpp

@@ -64,6 +64,8 @@ public:
 
 	ssize_t write(const void *buffer, size_t buffer_size);
 
+	void flush();
+
 	const char *getPort() const;
 
 	uint32_t getBaudrate() const;