def attr_configurable_protocols nm
      attr_configurable_arr(nm, :default => OnStomp::Connections.supported) do |vers|
        OnStomp::Connections.select_supported(vers).tap do |valid|
          raise OnStomp::UnsupportedProtocolVersionError, vers.inspect if valid.empty?
        end
      end
    end
def attr_configurable_protocols nm
      attr_configurable_arr(nm, :default => OnStomp::Connections.supported) do |vers|
        OnStomp::Connections.select_supported(vers).tap do |valid|
          raise OnStomp::UnsupportedProtocolVersionError, vers.inspect if valid.empty?
        end
      end
    end
Creates a readable and writeable attribute with the given name that
 defaults to the {OnStomp::Connections.supported supported} protocol
 versions and is {OnStomp::Connections.select_supported filtered} to
 those versions when assigned. Corresponds to which protocol versions
 should be used for a given client's connection.
 @param [Symbol] nm name of attribute