@Override
        public SegmentInputStreamProvider getSegmentInputStreamProvider(final String streamTypeName) {
            return inputStreamMap.computeIfAbsent(streamTypeName, k -> {
                final InternalSource source = getChild(k);
                if (source == null) {
                    return null;
                }
                return new SegmentInputStreamProvider(source, k);
            });
        }
Gets the output stream for this stream target.
stroom-data/stroom-data-store-mock/src/main/java/stroom/data/store/mock/MockStore.java