doc/README: add note re qmap/qhash type projection

README.md

@@ -74,10 +74,12 @@ MIQT is a clean-room binding that does not use any code from other Qt bindings.
 
 Most functions are implemented 1:1. [The Qt documentation](https://doc.qt.io/qt-5/classes.html) should be used.
 
-The `QByteArray`, `QString`, `QList<T>`, and `QVector<T>` types are projected as plain Go `[]byte`, `string`, and `[]T`. Therefore, you can't call any of QByteArray/QString/QList/QVector's helper methods, you must use some Go equivalent method instead.
+The `QByteArray`, `QString`, `QList<T>`, `QVector<T>`, `QMap<K,V>`, `QHash<K,V>` types are projected as plain Go `[]byte`, `string`, `[]T`, and `map[K]V`. Therefore, you can't call any of the Qt type's methods, you must use some Go equivalent method instead.
 
 - Go strings are internally converted to QString using `QString::fromUtf8`. Therefore, the Go string must be UTF-8 to avoid [mojibake](https://en.wikipedia.org/wiki/Mojibake). If the Go string contains binary data, the conversion would corrupt such bytes into U+FFFD (<28>). On return to Go space, this becomes `\xEF\xBF\xBD`.
 
+- The iteration order of a Qt QMap/QHash will differ from the Go map iteration order. QMap is iterated by key order, but Go maps and QHash iterate in an undefined internal order.
+
 Where Qt returns a C++ object by value (e.g. `QSize`), the binding may have moved it to the heap, and in Go this may be represented as a pointer type. In such cases, a Go finalizer is added to automatically delete the heap object. This means code using MIQT can look basically similar to the Qt C++ equivalent code.
 
 The `connect(sourceObject, sourceSignal, targetObject, targetSlot)` is projected as `targetObject.onSourceSignal(func()...)`.