delegate.pack(inputs, new DelegatingDataTarget(output) {
            @Override
            public OutputStream openOutput() throws IOException {
                return new SnappyFramedOutputStream(super.openOutput());
            }
        });
    }

    @Override
    public void unpack(DataSource input, DataTargetFactory targetFactory) throws IOException {

    }

    private void onTextEvent(StyledTextOutputEvent textOutputEvent) {
        if (textOutputEvent.getLogLevel() != null) {
            listener.onOutput(textOutputEvent);
        } else {
            listener.onOutput(textOutputEvent.withLogLevel(logLevel.get()));
        }
    }

//     computations, since they're part of the gradient for a loop in the
//     forward-pass.
//     TODO(skyewm): revisit this. Should we create WhileContexts for all loops,
//     even if we don't need them?
// * cond_output: if non-null, the output of the predicate is returned. This
//     will always be a LoopCond node.
//
// Returns an error if the while loop could not be fully constructed.
//

            new_output,
            absl::StrCat("CheckNumerics failed for output ", oidx, "(",
                         new_output.name(), ") from cluster ", cluster_name));
        new_output = check_numerics_op;
      }

      ops::_XlaMerge xla_merge_op(s.WithOpName("merge_oidx_", oidx),
                                  Output(old_node, oidx), new_output);

    }

    @Override
    void startInput() {
    }

    @Override
    void handlePrompt(RenderableOutputEvent event) {
        delegate.onOutput(event);
    }

    @Override
    void finishInput(RenderableOutputEvent event) {
        delegate.onOutput(event);
    }

    private void scheduleUpdateNow() {
        ScheduledFuture<?> ignored = executor.scheduleAtFixedRate(new Runnable() {
            @Override
            public void run() {
                try {
                    onOutput(new UpdateNowEvent(clock.getCurrentTime()));
                } catch (Throwable t) {
                    // this class is used as task in a scheduled executor service, so it must not throw any throwable,

                        useJUnitJupiter()
                    }
                }
            }
            tasks.test {
                onOutput(
                    KotlinClosure2<TestDescriptor, TestOutputEvent, Any>({ descriptor, event ->
                        println("onOutput:" + descriptor.displayName + ":" + event.message)
                    })
                )
            }

        this.stdoutChain = stdoutChain;
        this.stderrChain = stderrChain;
    }

    @Override
    public void onOutput(OutputEvent event) {
        if (event.getLogLevel() == null) {
            dispatch(event, stdoutChain);
            dispatch(event, stderrChain);
        } else if (event.getLogLevel() == LogLevel.ERROR) {

        when:
        bridge.onOutput(eventWithBuildOperationId)

        then:
        1 * buildOperationProgressEventEmitter.emit(_, _, _) >> { OperationIdentifier operationIdentifier, long timestamp, Object details ->
            assert operationIdentifier == testOperationId
            assert details == eventWithBuildOperationId
        }


        when:
        bridge.onOutput(eventWithFallbackBuildOperationId)

        }

        TestMethodResult methodResult = currentTestMethods.get(testDescriptor);
        if (methodResult == null) {
            outputWriter.onOutput(classResult.getId(), outputEvent);
        } else {
            outputWriter.onOutput(classResult.getId(), methodResult.getId(), outputEvent);
        }
    }

    private static String findEnclosingClassName(TestDescriptor testDescriptor) {