private com.google.protobuf.SingleFieldBuilderV3<
              com.google.cloud.tasks.v2beta2.HttpTarget.Header,
              com.google.cloud.tasks.v2beta2.HttpTarget.Header.Builder,
              com.google.cloud.tasks.v2beta2.HttpTarget.HeaderOrBuilder>
          getHeaderFieldBuilder() {
        if (headerBuilder_ == null) {
          headerBuilder_ =
              new com.google.protobuf.SingleFieldBuilderV3<
                  com.google.cloud.tasks.v2beta2.HttpTarget.Header,
                  com.google.cloud.tasks.v2beta2.HttpTarget.Header.Builder,
                  com.google.cloud.tasks.v2beta2.HttpTarget.HeaderOrBuilder>(
                  getHeader(), getParentForChildren(), isClean());
          header_ = null;
        }
        return headerBuilder_;
      }
<pre>
header embodying a key and a value.
</pre>

<code>.google.cloud.tasks.v2beta2.HttpTarget.Header header = 1;</code>
java-tasks/proto-google-cloud-tasks-v2beta2/src/main/java/com/google/cloud/tasks/v2beta2/HttpTarget.java