class ElasticAPM::OpenTracing::Span

def set_label(key, val)
  if elastic_span.is_a?(Transaction)
    case key.to_s
    when 'type'
      elastic_span.type = val
    when 'result'
      elastic_span.result = val
    when /user\.(\w+)/
      set_user_value($1, val)
    else
      elastic_span.context.labels[key] = val
    end
  else
    elastic_span.context.labels[key] = val
  end
end