public static Flow<ByteString, ByteString, NotUsed> flow(String callbackName) {
    ByteString cb = ByteString.fromString(callbackName);
    return Flow.of(ByteString.class)
        .map(
            (msg) -> {
              return formatted(cb, msg);
            }
public static Flow<ByteString, ByteString, NotUsed> flow(String callbackName) {
    ByteString cb = ByteString.fromString(callbackName);
    return Flow.of(ByteString.class)
        .map(
            (msg) -> {
              return formatted(cb, msg);
            }
public static Flow < ByteString , ByteString , NotUsed > flow ( String callbackName ) { ByteString cb = ByteString . fromString ( callbackName ) ; return Flow . of ( ByteString . class ) . map ( ( msg ) - > { return formatted ( cb , msg ) ; }
Produces a flow of ByteString with a prepended block and a script wrapper.

@param callbackName the javascript callback method.
@return a flow of ByteString elements.
Produces a flow of ByteString with a prepended block and a script wrapper .