void advanceNext() {
                while (fieldIterator.hasNext()) {
                    Map.Entry<String, Inspector> nextEntry = fieldIterator.next();
                    String fieldName = nextEntry.getKey();
                    next = toValue(nextEntry);
                    if ( next != null && ! summaryData.shadowed(fieldName) && ! summaryData.removed(fieldName))
                        return;
                }
                next = null;
            }
The next value or null if none, eagerly read because we need to skip removed and overwritten values
container-search/src/main/java/com/yahoo/prelude/fastsearch/FastHit.java