@Override
  public int read(byte[] b, int off, int len) throws IOException {
    checkPositionIndexes(off, off + len, b.length);
    return readInternal(b, off, len);
  }
{@link InputStream} for reading from a file's {@link RegularFile}.

@author Colin Decker
jimfs/src/main/java/com/google/common/jimfs/JimfsInputStream.java