# Package io.flutter.util

- Interface Summary
  Interface | Description
  --- | ---
  Predicate<T> |
  ViewUtils.DisplayUpdater |
  ViewUtils.ViewVisitor | Allows to visit a view.

- Class Summary
  Class | Description
  --- | ---
  HandlerCompat | Compatability wrapper over `Handler`.
  PathUtils |
  Preconditions | Static convenience methods that help a method or constructor check whether it was invoked correctly (that is, whether its preconditions were met).
  TraceSection |
  ViewUtils |