An effect to run a race for the given effects.

Named Race

perform id, %Race{
  effects: [
    effect1,
    effect2
  ]
}
# If effect2 resolves faster than effect1 with :somevalue,
# the race returns the :somevalue

Anonymous race

perform id, %Race{
  effects: [
    effect1: effect1,
    effect2: effect2
  ]
}
# If effect2 resolves faster than effect1 with :somevalue,
# the race returns the {effect2: :somevalue}