@java.lang.Override
    public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io.IOException {
      if (authMethod_
          != com.google.storagetransfer.v1.proto.TransferTypes.S3CompatibleMetadata.AuthMethod
              .AUTH_METHOD_UNSPECIFIED
              .getNumber()) {
        output.writeEnum(1, authMethod_);
      }
      if (requestModel_
          != com.google.storagetransfer.v1.proto.TransferTypes.S3CompatibleMetadata.RequestModel
              .REQUEST_MODEL_UNSPECIFIED
              .getNumber()) {
        output.writeEnum(2, requestModel_);
      }
      if (protocol_
          != com.google.storagetransfer.v1.proto.TransferTypes.S3CompatibleMetadata.NetworkProtocol
              .NETWORK_PROTOCOL_UNSPECIFIED
              .getNumber()) {
        output.writeEnum(3, protocol_);
      }
      if (listApi_
          != com.google.storagetransfer.v1.proto.TransferTypes.S3CompatibleMetadata.ListApi
              .LIST_API_UNSPECIFIED
              .getNumber()) {
        output.writeEnum(4, listApi_);
      }
      getUnknownFields().writeTo(output);
    }
<pre>
The Listing API to use for discovering objects. When not specified,
Transfer Service will attempt to determine the right API to use.
</pre>

<code>.google.storagetransfer.v1.S3CompatibleMetadata.ListApi list_api = 4;</code>

@return The listApi.
java-storage-transfer/proto-google-cloud-storage-transfer-v1/src/main/java/com/google/storagetransfer/v1/proto/TransferTypes.java