public com.google.protobuf.ByteString getNextPageTokenBytes() {
        java.lang.Object ref = nextPageToken_;
        if (ref instanceof String) {
          com.google.protobuf.ByteString b =
              com.google.protobuf.ByteString.copyFromUtf8((java.lang.String) ref);
          nextPageToken_ = b;
          return b;
        } else {
          return (com.google.protobuf.ByteString) ref;
        }
      }
<pre>
The list next page token.
</pre>

<code>string next_page_token = 2;</code>

@return The bytes for nextPageToken.
java-storage-transfer/proto-google-cloud-storage-transfer-v1/src/main/java/com/google/storagetransfer/v1/proto/TransferProto.java