code: public int readFully(byte b[], int off, int len) throws IOException {
          IOUtils.readFully(inStream, b, off, len);
          return len;
      }
docs: Read a number of bytes from the input stream, blocking until all
  requested bytes are read or end of file is reached.
  
  @param b the buffer to bill
  @param off offset in buffer where to start filling
  @param len how many bytes we should read
  @return the total number of bytes read
  @throws IOException if end of file reached without getting all requested
  bytes