when<TResult extends Object?> method

  1. @optionalTypeArgs
TResult when<TResult extends Object?>(
  1. TResult $default(
    1. List<NameServerConfig>? servers,
    2. HostsWrapper? hosts,
    3. XrayAddress? clientIp,
    4. String? tag,
    5. DnsQueryStrategy? queryStrategy,
    6. bool? disableCache,
    7. bool? serveStale,
    8. int? serveExpiredTTL,
    9. bool? disableFallback,
    10. bool? disableFallbackIfMatch,
    11. bool? enableParallelQuery,
    12. bool? useSystemHosts,
    )
)

A switch-like method, using callbacks.

As opposed to map, this offers destructuring. It is equivalent to doing:

switch (sealedClass) {
  case Subclass(:final field):
    return ...;
  case Subclass2(:final field2):
    return ...;
}

Implementation

@optionalTypeArgs TResult when<TResult extends Object?>(TResult Function( List<NameServerConfig>? servers,  HostsWrapper? hosts,  XrayAddress? clientIp,  String? tag,  DnsQueryStrategy? queryStrategy,  bool? disableCache,  bool? serveStale,  int? serveExpiredTTL,  bool? disableFallback,  bool? disableFallbackIfMatch,  bool? enableParallelQuery,  bool? useSystemHosts)  $default,) {final _that = this;
switch (_that) {
case _DNSConfig():
return $default(_that.servers,_that.hosts,_that.clientIp,_that.tag,_that.queryStrategy,_that.disableCache,_that.serveStale,_that.serveExpiredTTL,_that.disableFallback,_that.disableFallbackIfMatch,_that.enableParallelQuery,_that.useSystemHosts);case _:
  throw StateError('Unexpected subclass');

}
}