Update README.md

Author: akarnokd

README.md

@@ -2,6 +2,12 @@
 
 Library for interoperation between RxJava 3 and JDK 21's Virtual Threads (aka Fibers, Project Loom).
 
+# RxJava 4.0 now has integrated virtual scheduler and virtual operators
+
+This library won't be developed further.
+
+-------
+
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