spec.instant.child2Started
                        spec.thread.block()
                        spec.instant.child2Finished
                    }
                })
            })
            outer.leaseFinish()
        }

        then:
        instant.child2Started > instant.child1Finished || instant.child1Started > instant.child2Finished

        cleanup:

import java.time.Duration;
import java.time.Instant;

/**
 * Represents when cache cleanup should be triggered.
 *
 * @since 8.0
 */
public interface CleanupFrequency {
    /**
     * Trigger cleanup once every 24 hours.
     */
    CleanupFrequency DAILY = new CleanupFrequency() {
        @Override
        public boolean requiresCleanup(@Nullable Instant lastCleanupTime) {
            if (lastCleanupTime == null) {

                state.applyToMutableState {
                    assert state.hasMutableState()
                    instant.thread2
                }
                assert !state.hasMutableState()
            }
        }

        then:
        instant.thread2 > instant.thread1
    }

    def "a given thread can only access the state of one project at a time"() {
        given:

                workerLeaseService.withLocks([taskLease]) {
                    instant.worker1Locked
                    thread.block()
                    instant.worker1Unlocked
                }
            }
            start {
                thread.blockUntil.worker1Locked
                workerLeaseService.withLocks([taskLease]) {
                    instant.worker2Locked
                    assert lockIsHeld(taskLease)

     *             to {@link #MavenBuildTimestamp(Instant, String)} instead.
     */
    @Deprecated
    public MavenBuildTimestamp(Instant time, Properties properties) {
        this(time, properties != null ? properties.getProperty(BUILD_TIMESTAMP_FORMAT_PROPERTY) : null);
    }

    public MavenBuildTimestamp(Instant time, String timestampFormat) {

            start {
                lifecycle.use {
                    instant.running
                    thread.block()
                    instant.finished
                }
            }
            thread.blockUntil.running
            lifecycle.stop()
            instant.stopped
        }

        then:
        instant.finished < instant.stopped
    }

        def execution = testExecution({
            instant.executionStarted
            println("I'm running!")
            thread.block()
            instant.executionFinished
        })

        when:
        async {
            queue.submit(execution)
            execution.await()
            instant.awaitFinished
        }

        then:
        instant.awaitFinished > instant.executionFinished
    }

    }

    Instant getEnd() {
        def instant = end.get()
        if (instant == null) {
            throw new IllegalStateException("Operation '$name' has not completed yet.")
        }
        return instant
    }

    Duration getDuration() {
        return getEnd() - start
    }

    void completed(Instant when) {
        end.compareAndSet(null, when)
    }

        getLastCleanupTime()
            .ifPresent(this::performCleanupIfNecessary);
    }

    private void performCleanupIfNecessary(Instant lastCleanupTime) {
        if (LOGGER.isDebugEnabled()) {
            Duration timeSinceLastCleanup = Duration.between(lastCleanupTime, Instant.now());
            LOGGER.debug("{} has last been fully cleaned up {} hours ago", cleanableStore.getDisplayName(), timeSinceLastCleanup.toHours());
        }

        async {
            start {
                def result = userInputReader.readInput()
                instant.read
                assert result == response
            }
            thread.block()
            instant.put
            userInputReader.putInput(response)
        }
        instant.read > instant.put

        where:
        response << [
            new UserInputReader.TextResponse("answer"),