The VirtualHost class is a utility class for handling multiple hosts on multiple sources, by using a named-based approach.

abstract class VirtualHost {
 /**
  * Get the [Stream] of [HttpRequest]s, not matching any hosts. If unused, the
  * default implementation will result in a [HttpHeaders.FORBIDDEN] response.
  */
 Stream<HttpRequest> get unhandled;

 /**
  * Construct a new [VirtualHost].
  *
  * The optional [source] is a shortcut for calling [addSource].
  *
  * Example of usage:
  *
  *   HttpServer.bind(..., 80).then((server) {
  *     var virtualHost = new VirtualHost(server);
  *     virtualServer.addHost('static.myserver.com')
  *         .listen(...);
  *     virtualServer.addHost('cache.myserver.com')
  *         .listen(...);
  *   })
  */
 factory VirtualHost([Stream<HttpRequest> source]) => new _VirtualHost(source);

 /**
  * Provide another source of [HttpRequest]s in the form of a [Stream].
  */
 void addSource(Stream<HttpRequest> source);


 /**
  * Add a host to the [VirtualHost] instance. The host can be either a specific
  * domain (`my.domain.name`) or a wildcard-based domain name
  * (`*.domain.name`). The former will only match the specific domain name
  * while the latter will match any series of sub-domains.
  *
  * If both `my.domain.name` and `*.domain.name` is specified, the most
  * qualified will take precedence, `my.domain.name` in this case.
  */
 Stream<HttpRequest> addHost(String host);
}