code: public void addHeader (@Nonnull @Nonempty final String sName, @Nullable final String sValue)
    {
      if (sValue != null)
        _addHeader (sName, sValue);
    }
docs: Add the passed header as is.
  
  @param sName
  Header name. May neither be <code>null</code> nor empty.
  @param sValue
  The value to be set. May be <code>null</code> in which case nothing
  happens.