code: function evenly(iterables) {
      const iterators = iterables.map(iterable => createIterator(iterable, { strict: false }));
      const empties = new Set();
  
      const count = iterators.length;
      let index = -1;
  
      /**
       * Returns next iterator.
       *
       * Returns the first iterator after the last one.
       *
       * @returns {Iterator}
       */
      function step() {
          // Back to the first iterator.
          if (index === count - 1) {
              index = -1;
          }
  
          // Go to the next iterator.
          index++;
  
          // Ignore empty iterators.
          while(empties.has(index)) {
              if (index === count - 1) {
                  index = -1;
              }
  
              index++;
          }
  
          return iterators[index];
      }
  
      /**
       * Returns next value.
       *
       * @returns {{done: boolean, value: *}}
       */
      function next() {
          // Exit if all iterators are traversed.
          if (empties.size === count) {
              return done;
          }
  
          // Go to the next iterator.
          const iter = step();
  
          const res = iter.next();
  
          // Mark iterator as empty and go to the next.
          if (res.done) {
              empties.add(index);
  
              return next();
          }
  
          return res;
      }
  
      return { next, [Symbol.iterator]() { return this; } };
  }
docs: Returns an Iterator, that traverses iterators evenly.
  
  This is reminiscent of the traversing of several arrays
  
  @example
  const evenly = require('ho-iter').evenly;
  
  const arr1 = [1, 2];
  const arr2 = [3, 4];
  
  const set1 = new Set([1, 2]);
  const set2 = new Set([3, 4]);
  
  for (let i = 0; i < arr1.length; i++) {
  console.log(arr1[i]);
  console.log(arr2[i]);
  }
  
  // 1 3 2 4
  
  for (let item of evenly(set1, set2)) {
  console.log(item);
  }
  
  // 1 3 2 4
  
  @param {Iterable[]} iterables - iterable objects or iterators.
  @returns {Iterator}