Add debug for setResourceName

Author: ygree

Diff for: dd-trace-core/src/main/java/datadog/trace/core/DDSpanContext.java

@@ -414,6 +414,7 @@ public byte getResourceNamePriority() {
   }
 
   public void setResourceName(final CharSequence resourceName, byte priority) {
+    log.debug("setResourceName `{}` with priority `{}`", resourceName, priority);
     if (null == resourceName) {
       return;
     }