Informative blocking queue now accepts non-null references only

Author: wfouche

tulip-runtime/src/main/kotlin/io/github/wfouche/tulip/core/Tulip.kt

@@ -56,7 +56,7 @@ fun getProcessCpuTime(): Long {
 
 /*-------------------------------------------------------------------------*/
 
-class InformativeBlockingQueue<E>(val capacity: Int) : BlockingQueue<E>(capacity) {}
+class InformativeBlockingQueue<E>(val capacity: Int) : BlockingQueue<E & Any>(capacity) {}
 
 typealias Java_Queue<E> = InformativeBlockingQueue<E>