checkPositionIndexes(off, off + len, buf.length);

          int i = off;
          for (; i < off + len; i++) {
            int b = read();
            if (b == -1) {
              int read = i - off;
              return read == 0 ? -1 : read;
            }
            buf[i] = (byte) b;
          }
          return i - off;
        }

        @Override