public Builder clearHost() {
      host_ = getDefaultInstance().getHost();
      bitField0_ = (bitField0_ & ~0x00000008);
      onChanged();
      return this;
    }
<pre>
Output only. The host that the task is sent to.

For more information, see
[How Requests are
Routed](https://cloud.google.com/appengine/docs/standard/python/how-requests-are-routed).

The host is constructed as:


* `host = [application_domain_name]`&lt;/br&gt;
  `| [service] + '.' + [application_domain_name]`&lt;/br&gt;
  `| [version] + '.' + [application_domain_name]`&lt;/br&gt;
  `| [version_dot_service]+ '.' + [application_domain_name]`&lt;/br&gt;
  `| [instance] + '.' + [application_domain_name]`&lt;/br&gt;
  `| [instance_dot_service] + '.' + [application_domain_name]`&lt;/br&gt;
  `| [instance_dot_version] + '.' + [application_domain_name]`&lt;/br&gt;
  `| [instance_dot_version_dot_service] + '.' + [application_domain_name]`

* `application_domain_name` = The domain name of the app, for
  example &lt;app-id&gt;.appspot.com, which is associated with the
  queue's project ID. Some tasks which were created using the App Engine
  SDK use a custom domain name.

* `service =`
[service][google.cloud.tasks.v2beta2.AppEngineRouting.service]

* `version =`
[version][google.cloud.tasks.v2beta2.AppEngineRouting.version]

* `version_dot_service =`
  [version][google.cloud.tasks.v2beta2.AppEngineRouting.version] `+ '.' +`
  [service][google.cloud.tasks.v2beta2.AppEngineRouting.service]

* `instance =`
[instance][google.cloud.tasks.v2beta2.AppEngineRouting.instance]

* `instance_dot_service =`
  [instance][google.cloud.tasks.v2beta2.AppEngineRouting.instance] `+ '.'
  +` [service][google.cloud.tasks.v2beta2.AppEngineRouting.service]

* `instance_dot_version =`
  [instance][google.cloud.tasks.v2beta2.AppEngineRouting.instance] `+ '.'
  +` [version][google.cloud.tasks.v2beta2.AppEngineRouting.version]

* `instance_dot_version_dot_service =`
  [instance][google.cloud.tasks.v2beta2.AppEngineRouting.instance] `+ '.'
  +` [version][google.cloud.tasks.v2beta2.AppEngineRouting.version] `+ '.'
  +` [service][google.cloud.tasks.v2beta2.AppEngineRouting.service]

If [service][google.cloud.tasks.v2beta2.AppEngineRouting.service] is empty,
then the task will be sent to the service which is the default service when
the task is attempted.

If [version][google.cloud.tasks.v2beta2.AppEngineRouting.version] is empty,
then the task will be sent to the version which is the default version when
the task is attempted.

If [instance][google.cloud.tasks.v2beta2.AppEngineRouting.instance] is
empty, then the task will be sent to an instance which is available when
the task is attempted.

If [service][google.cloud.tasks.v2beta2.AppEngineRouting.service],
[version][google.cloud.tasks.v2beta2.AppEngineRouting.version], or
[instance][google.cloud.tasks.v2beta2.AppEngineRouting.instance] is
invalid, then the task will be sent to the default version of the default
service when the task is attempted.
</pre>

<code>string host = 4;</code>

@return This builder for chaining.
java-tasks/proto-google-cloud-tasks-v2beta2/src/main/java/com/google/cloud/tasks/v2beta2/AppEngineRouting.java