docs: async function () {
  
          const log = []
  
          const a =       () => {                     log.push ('a')              }
          const b = async () => { await __.sleep (1); log.push ('b');             }
          const c =       () => {                     log.push ('c'); return 42   } // breaks here
          const d =       () => {                     log.push ('d');             } // will not be executed
  
          await __.each ([a, b, c], (fn, i, break_) =>
                                      __.then (fn, x => {
                                                      if (x === 42) break_ () }))
  
          $assert (log, ['a', 'b', 'c'])
      }