public FilterProgressMonitor logFilter(final ProcessorFilter filter,
                                           final int initialQueueSize) {
        final FilterProgressMonitor filterProgressMonitor = new FilterProgressMonitor(
                filter,
                initialQueueSize);
        filterProgressMonitorList.add(filterProgressMonitor);
        return filterProgressMonitor;
    }
Holds state relating to the progress of creation of tasks by the master node
stroom-processor/stroom-processor-impl/src/main/java/stroom/processor/impl/ProgressMonitor.java