add a possibility to flush the serial TX buffer on the console.

src/SerialConsole.cpp

@@ -20,9 +20,7 @@ void consolePrintf(const char *format, ...)
     va_start(arg, format);
     console->vprintf(format, arg);
     va_end(arg);
-#ifdef ARCH_ESP32
     console->flush();
-#endif
 }
 
 SerialConsole::SerialConsole() : StreamAPI(&Port), RedirectablePrint(&Port), concurrency::OSThread("SerialConsole")
@@ -51,6 +49,10 @@ int32_t SerialConsole::runOnce()
     return runOncePart();
 }
 
+void SerialConsole::flush() {
+    Port.flush();
+}
+
 // For the serial port we can't really detect if any client is on the other side, so instead just look for recent messages
 bool SerialConsole::checkIsConnected()
 {

src/SerialConsole.h

@@ -26,6 +26,8 @@ class SerialConsole : public StreamAPI, public RedirectablePrint, private concur
 
     virtual int32_t runOnce() override;
 
+    void flush();
+
   protected:
 
     /// Check the current underlying physical link to see if the client is currently connected