ObjectFlagProperty<T> constructor

ObjectFlagProperty<T>(String name, T value, { String ifPresent, String ifNull, bool showName: false, DiagnosticLevel level: DiagnosticLevel.info })

Create a diagnostics property for values that can be present (non-null) or absent (null), but for which the exact value's Object.toString representation is not very transparent (e.g. a callback).

The showName and level arguments must not be null. Additionally, at least one of ifPresent and ifNull must not be null.

Implementation 

ObjectFlagProperty(String name, T value, {
  this.ifPresent,
  String ifNull,
  bool showName = false,
  DiagnosticLevel level  = DiagnosticLevel.info,
}) : assert(ifPresent != null || ifNull != null),
     assert(showName != null),
     assert(level != null),
     super(
  name,
  value,
  showName: showName,
  ifNull: ifNull,
  level: level,
);