Do not block-drain serial port before closing

src/main/c/Posix/PosixHelperFunctions.h

@@ -2,7 +2,7 @@
  * PosixHelperFunctions.h
  *
  *       Created on:  Mar 10, 2015
- *  Last Updated on:  Jan 24, 2022
+ *  Last Updated on:  Feb 14, 2022
  *           Author:  Will Hedgecock
  *
  * Copyright (C) 2012-2022 Fazecast, Inc.
@@ -98,6 +98,8 @@ void searchForComPorts(serialPortVector* comPorts);
 // Apple-specific functionality
 #elif defined(__APPLE__)
 
+#define fdatasync fsync
+
 #include <termios.h>
 typedef speed_t baud_rate;
 void searchForComPorts(serialPortVector* comPorts);

src/main/c/Posix/SerialPort_Posix.c

@@ -2,7 +2,7 @@
  * SerialPort_Posix.c
  *
  *       Created on:  Feb 25, 2012
- *  Last Updated on:  Jan 28, 2022
+ *  Last Updated on:  Feb 14, 2022
  *           Author:  Will Hedgecock
  *
  * Copyright (C) 2012-2022 Fazecast, Inc.
@@ -803,8 +803,7 @@ JNIEXPORT jlong JNICALL Java_com_fazecast_jSerialComm_SerialPort_closePortNative
 	tcsetattr(port->handle, TCSANOW, &options);
 
 	// Unblock, unlock, and close the port
-	fsync(port->handle);
-	tcdrain(port->handle);
+	fdatasync(port->handle);
 	tcflush(port->handle, TCIOFLUSH);
 	flock(port->handle, LOCK_UN | LOCK_NB);
 	while (close(port->handle) && (errno == EINTR))

src/main/java/com/fazecast/jSerialComm/SerialPort.java

@@ -1765,6 +1765,8 @@ public final class SerialPort
 			
 			try
 			{
+				// Wait until the event-reading thread returns. This thread MUST return or the serial port will
+				//   be in an unspecified, possibly unrecoverable state
 				do
 				{
 					serialEventThread.join(500);