docs: @Override
      public FilterChannel position(long newPosition) throws IOException
      {
          if (!isOpen())
          {
              throw new ClosedChannelException();
          }
          int skip = (int) (newPosition - position());
          if (skip < 0)
          {
              throw new UnsupportedOperationException("backwards position not supported");
          }
          if (skip > skipBuffer.capacity())
          {
              throw new UnsupportedOperationException(skip+" skip not supported maxSkipSize="+maxSkipSize);
          }
          if (skip > 0)
          {
              if (skipBuffer == null)
              {
                  throw new UnsupportedOperationException("skip not supported maxSkipSize="+maxSkipSize);
              }
              skipBuffer.clear();
              skipBuffer.limit(skip);
              if (in != null)
              {
                  read(skipBuffer);
              }
              else
              {
                  write(skipBuffer);
              }
          }
          return this;
      }