@SuppressWarnings({
    "PMD.UncommentedEmptyMethodBody",
    "PMD.EmptyMethodInAbstractClassShouldBeAbstract"
  })
  protected void write(Output output, String key, Object value) throws EncodeException {}
Writes data for it's children.

@param output output writer.
@param key name for piece of data.
@param value piece of data.
@throws EncodeException in case of write errors
form/src/main/java/feign/form/multipart/AbstractWriter.java