description

# fork method Null safety

Zone fork (

1. {ZoneSpecification? specification,
2. Map<Object?, Object?>? zoneValues}

)

Creates a new zone as a child of `this`.

The new zone uses the closures in the given `specification` to override the current's zone behavior. All specification entries that are `null` inherit the behavior from the parent zone (`this`).

The new zone inherits the stored values (accessed through operator []) of this zone and updates them with values from `zoneValues`, which either adds new values or overrides existing ones.

Note that the fork operation is interceptible. A zone can thus change the zone specification (or zone values), giving the forking zone full control over the child zone.

## Implementation

    Zone fork(
        {ZoneSpecification? specification, Map<Object?, Object?>? zoneValues});