code: async function bulkCopy(srcset, createDestinationDirs=true, defaultFilemode=0o750, defaultDirmode=0o777){
      // create destination directories in advance ?
      if (createDestinationDirs === true){
          // get unique paths from filelist
          const dstDirs = Array.from(new Set(srcset.map((set) => _path.dirname(set[1]))));
  
          // create dirs
          for (let i=0;i<dstDirs.length;i++){
              await _mkdirp(dstDirs[i], defaultDirmode, true);
          }
      }
  
      // create tasks
      const tasks = srcset.map((set) => _async.PromiseResolver(_copy, set[0], set[1], set[2] || defaultFilemode));
  
      // resolve tasks in parallel with task limit 100
      await _async.parallel(tasks, 100);
  }
docs: copy a set of files simultanous