guava/src/com/google/common/collect/MapMakerInternalMap.java
V getLiveValue(E entry) {
    if (entry.getKey() == null) {
      return null;
    }
    V value = entry.getValue();
    if (value == null) {
      return null;
    }
    return value;
  }
V getLiveValue(E entry) {
    if (entry.getKey() == null) {
      return null;
    }
    V value = entry.getValue();
    if (value == null) {
      return null;
    }
    return value;
  }
Gets the value from an entry. Returns {@code null} if the entry is invalid, partially-collected
or computing.