public Builder clearKey() {
        key_ = getDefaultInstance().getKey();
        bitField0_ = (bitField0_ & ~0x00000001);
        onChanged();
        return this;
      }
<pre>
The Key of the header.
</pre>

<code>string key = 1;</code>

@return This builder for chaining.
java-tasks/proto-google-cloud-tasks-v2beta3/src/main/java/com/google/cloud/tasks/v2beta3/HttpTarget.java