guavasupport/src/main/java/com/streamsets/pipeline/lib/io/fileref/AbstractWrapperStream.java
@Override
  public int read(byte[] b, int offset, int len) throws IOException {
    checkState(InputStream.class);
    return  ((InputStream)stream).read(b, offset, len);
  }
@Override
  public int read(byte[] b, int offset, int len) throws IOException {
    checkState(InputStream.class);
    return  ((InputStream)stream).read(b, offset, len);
  }
@ Override public int read ( byte [ ] b , int offset , int len ) throws IOException { checkState ( InputStream . class ) ; return ( ( InputStream ) stream ) . read ( b , offset , len ) ; }
InputStream
InputStream