@SuppressWarnings("NullableProblems")
    @Override
    public int read(byte[] b) throws IOException {
        checkOpenEntry();
        return segmentInputStream.read(b);
    }
Wrapper for a nested input stream.
<p>
You must call getNextEntry and closeEntry like the ZIP API.
stroom-data/stroom-data-store-impl-fs/src/main/java/stroom/data/store/impl/fs/RANestedInputStream.java