defimpl String.Chars, for: Exkad.Node.Descriptor do 

  def to_string(%Exkad.Node.Descriptor{loc: loc} = d) when is_pid(loc) do
    "|#{d.id} located @ #{inspect d.loc}|"
  end

  def to_string(d) do
    "|#{d.id} located @ #{d.loc}|"
  end

end