code: public synchronized void invalidateFile(WriterPoolMember f)
      throws IOException {
          try {
              destroyWriter(f);
          } catch (Exception e) {
              // Convert exception.
              throw new IOException(e.getMessage());
          }
          // It'll have been closed.  Rename with an '.invalid' suffix so it
          // gets attention.
          File file = f.getFile();
          file.renameTo(new File(file.getAbsoluteFile() +
                  WriterPoolMember.INVALID_SUFFIX));
      }
docs: Close and discard a writer that experienced a potentially-corrupting
  error.
  @param f writer with problem
  @throws IOException