public Builder clearUsername() {
      username_ = getDefaultInstance().getUsername();
      bitField0_ = (bitField0_ & ~0x00000002);
      onChanged();
      return this;
    }
<pre>
Optional. The username of the user to be queried for credentials.
The default value of this field is CloudOwner&#64;gve.local.
The provided value must be one of the following:
CloudOwner&#64;gve.local,
solution-user-01&#64;gve.local,
solution-user-02&#64;gve.local,
solution-user-03&#64;gve.local,
solution-user-04&#64;gve.local,
solution-user-05&#64;gve.local,
zertoadmin&#64;gve.local.
</pre>

<code>string username = 2 [(.google.api.field_behavior) = OPTIONAL];</code>

@return This builder for chaining.
java-vmwareengine/proto-google-cloud-vmwareengine-v1/src/main/java/com/google/cloud/vmwareengine/v1/ShowVcenterCredentialsRequest.java