Initially we were thinking of creating plugin. Then we found out that people uses various IDE's when developing several platforms/systems and idea was dropped.
Now the typical work flow is that you code using your favorite IDE and on second screen you have analysis running without stepping into way.
What comes to Qt, we implemented small logging library that does basic stuff and OS level CPU and Memory usage logging. It might be good idea to check latest Qt logging API and support for those as well.
Just just launch your app from the console. qDebug, qWarning etc. will be printed to the console too (stdout/stderr). Make sure you don't define QT_NO_DEBUG_OUTPUT -- see http://doc.qt.io/qt-5/debug.html for more info.
One thing in you code is that in your receive function your are looping over each byte you received and ask to update the widget. What is generally done when handling large amount of data in such small amount is that the processing is done in a different thread. Also the UI update should be batched, there's no real benefit to update your QPlainTextEdit content for every single byte you get.
@_JR_ You're welcome :) Personally I neither had any experience in writing iOS apps nor have the necessary hardware/keys/certificates for that. So any input on the subject will be useful (but I doubt that it will be possible to make any enhancements based on that).