public ObservableReversableMemberExpression(MemberExpression expression, ObservableExpressionBinder binder, string name, FieldInfo field)
     : this(binder.VisitObservable <TTarget>(expression.Expression, true), name, ReflectionHelper.CreateDynamicFieldGetter <TTarget, TMember>(field), ReflectionHelper.CreateDynamicFieldSetter <TTarget, TMember>(field))
 {
 }