public com.google.cloud.tasks.v2beta2.HttpTarget.HeaderOverride.Builder
        addHeaderOverridesBuilder(int index) {
      return getHeaderOverridesFieldBuilder()
          .addBuilder(
              index, com.google.cloud.tasks.v2beta2.HttpTarget.HeaderOverride.getDefaultInstance());
    }
<pre>
HTTP target headers.

This map contains the header field names and values.
Headers will be set when running the
[task is created][google.cloud.tasks.v2beta2.CloudTasks.CreateTask] and/or
[task is created][google.cloud.tasks.v2beta2.CloudTasks.BufferTask].

These headers represent a subset of the headers that will accompany the
task's HTTP request. Some HTTP request headers will be ignored or replaced.

A partial list of headers that will be ignored or replaced is:
* Any header that is prefixed with "X-CloudTasks-" will be treated
as service header. Service headers define properties of the task and are
predefined in CloudTask.
* Host: This will be computed by Cloud Tasks and derived from
  [HttpRequest.url][google.cloud.tasks.v2beta2.HttpRequest.url].
* Content-Length: This will be computed by Cloud Tasks.
* User-Agent: This will be set to `"Google-CloudTasks"`.
* `X-Google-*`: Google use only.
* `X-AppEngine-*`: Google use only.

`Content-Type` won't be set by Cloud Tasks. You can explicitly set
`Content-Type` to a media type when the
 [task is created][google.cloud.tasks.v2beta3.CloudTasks.CreateTask].
 For example, `Content-Type` can be set to `"application/octet-stream"` or
 `"application/json"`.

Headers which can have multiple values (according to RFC2616) can be
specified using comma-separated values.

The size of the headers must be less than 80KB.
Queue-level headers to override headers of all the tasks in the queue.
</pre>

<code>repeated .google.cloud.tasks.v2beta2.HttpTarget.HeaderOverride header_overrides = 3;
</code>
java-tasks/proto-google-cloud-tasks-v2beta2/src/main/java/com/google/cloud/tasks/v2beta2/HttpTarget.java