public boolean containsHeaders(java.lang.String key) {
    if (key == null) {
      throw new java.lang.NullPointerException();
    }
    return internalGetHeaders().getMap().containsKey(key);
  }
public boolean containsHeaders ( java . lang . String key ) { if ( key == null ) { throw new java . lang . NullPointerException ( ) ; } return internalGetHeaders ( ) . getMap ( ) . containsKey ( key ) ; }
<pre>
HTTP request headers.
This map contains the header field names and values.
Headers can be set when the
[task is created][google.cloud.tasks.v2beta3.CloudTasks.CreateTask].
Repeated headers are not supported but a header value can contain commas.
Cloud Tasks sets some headers to default values:
* `User-Agent`: By default, this header is
`"AppEngine-Google; (+http://code.google.com/appengine)"`.
This header can be modified, but Cloud Tasks will append
`"AppEngine-Google; (+http://code.google.com/appengine)"` to the
modified `User-Agent`.
If the task has a [body][google.cloud.tasks.v2beta3.AppEngineHttpRequest.body], Cloud
Tasks sets the following headers:
* `Content-Type`: By default, the `Content-Type` header is set to
`"application/octet-stream"`. The default can be overridden by explicitly
setting `Content-Type` to a particular media type when the
[task is created][google.cloud.tasks.v2beta3.CloudTasks.CreateTask].
For example, `Content-Type` can be set to `"application/json"`.
* `Content-Length`: This is computed by Cloud Tasks. This value is
output only.   It cannot be changed.
The headers below cannot be set or overridden:
* `Host`
* `X-Google-*`
* `X-AppEngine-*`
In addition, Cloud Tasks sets some headers when the task is dispatched,
such as headers containing information about the task; see
[request
headers](https://cloud.google.com/appengine/docs/python/taskqueue/push/creating-handlers#reading_request_headers).
These headers are set only when the task is dispatched, so they are not
visible when the task is returned in a Cloud Tasks response.
Although there is no specific limit for the maximum number of headers or
the size, there is a limit on the maximum size of the [Task][google.cloud.tasks.v2beta3.Task]. For more
information, see the [CreateTask][google.cloud.tasks.v2beta3.CloudTasks.CreateTask] documentation.
</pre>

<code>map&lt;string, string&gt; headers = 4;</code>