code: public static void append(Path self, InputStream stream) throws IOException {
          OutputStream out = Files.newOutputStream(self, CREATE, APPEND);
          try {
              IOGroovyMethods.leftShift(out, stream);
          } finally {
              closeWithWarning(out);
          }
      }
docs: Append binary data to the file.  It <strong>will not</strong> be
  interpreted as text.
  
  @param self   a Path
  @param stream stream to read data from.
  @throws java.io.IOException if an IOException occurs.
  @since 2.3.0