public void modifyReindexing(ApplicationId id, ApplicationReindexing emptyValue, UnaryOperator<ApplicationReindexing> modifications) {
        try (Lock lock = curator.lock(reindexingLockPath(id), Duration.ofMinutes(1))) {
            writeReindexingStatus(id, modifications.apply(readReindexingStatus(id).orElse(emptyValue)));
        }
    }
Reads, modifies and writes the application reindexing for this application, while holding its lock.
configserver/src/main/java/com/yahoo/vespa/config/server/application/ApplicationCuratorDatabase.java