public Builder mergeCustomAccount(
          com.google.cloud.websecurityscanner.v1.ScanConfig.Authentication.CustomAccount value) {
        if (customAccountBuilder_ == null) {
          if (authenticationCase_ == 2
              && authentication_
                  != com.google.cloud.websecurityscanner.v1.ScanConfig.Authentication.CustomAccount
                      .getDefaultInstance()) {
            authentication_ =
                com.google.cloud.websecurityscanner.v1.ScanConfig.Authentication.CustomAccount
                    .newBuilder(
                        (com.google.cloud.websecurityscanner.v1.ScanConfig.Authentication
                                .CustomAccount)
                            authentication_)
                    .mergeFrom(value)
                    .buildPartial();
          } else {
            authentication_ = value;
          }
          onChanged();
        } else {
          if (authenticationCase_ == 2) {
            customAccountBuilder_.mergeFrom(value);
          } else {
            customAccountBuilder_.setMessage(value);
          }
        }
        authenticationCase_ = 2;
        return this;
      }
<pre>
Authentication using a custom account.
</pre>

<code>
.google.cloud.websecurityscanner.v1.ScanConfig.Authentication.CustomAccount custom_account = 2;
</code>
java-websecurityscanner/proto-google-cloud-websecurityscanner-v1/src/main/java/com/google/cloud/websecurityscanner/v1/ScanConfig.java