code: private void mergeGlobalProperties(Map<String, Object> globalProperties, Map<String, Object> keenProperties,
                                         Map<String, Object> newEvent) {
          if (globalProperties != null) {
              // Clone globals so we don't modify the original
              globalProperties = new HashMap<String, Object>(globalProperties);
              Object keen = globalProperties.remove("keen");
              if (keen instanceof Map) {
                  keenProperties.putAll((Map)keen);
              }
              newEvent.putAll(globalProperties);
          }
      }
docs: Removes the "keen" key from the globalProperties map and, if a map was removed, then all of its pairs are added to the keenProperties map.
  Anything left in the globalProperties map is then added to the newEvent map.
  
  @param globalProperties
  @param keenProperties
  @param newEvent