def undefined_conversion_error_char(e)
      # Rubinius (as of 2.0.0.rc1) pre-quotes the error character.
      return e.error_char if rbx?
      # JRuby (as of 1.7.2) doesn't have an error_char field on
      # Encoding::UndefinedConversionError.
      return e.error_char.dump unless jruby?
      e.message[/^"[^"]+"/] # "
    end
def undefined_conversion_error_char(e)
      # Rubinius (as of 2.0.0.rc1) pre-quotes the error character.
      return e.error_char if rbx?
      # JRuby (as of 1.7.2) doesn't have an error_char field on
      # Encoding::UndefinedConversionError.
      return e.error_char.dump unless jruby?
      e.message[/^"[^"]+"/] # "
    end
Returns a string description of the character that caused an
 `Encoding::UndefinedConversionError`.

 @param e [Encoding::UndefinedConversionError]
 @return [String]