applied to randomly generated closed terms.
The benchmark indicates that fa consistently less memory, especially
in the major heap, yet fa' is faster, perhaps because it does not
involve mutable state.

Estimated testing time 3.33333m (20 benchmarks x 10s). Change using -quota SECS.
┌─────────┬──────────┬─────────┬──────────┬──────────┬────────────┐
│ Name    │ Time/Run │ mWd/Run │ mjWd/Run │ Prom/Run │ Percentage │
├─────────┼──────────┼─────────┼──────────┼──────────┼────────────┤
│ fa'(t0) │   7.42ms │  2.71Mw │   2.36kw │   2.36kw │     87.73% │
│ fa(t0)  │   7.77ms │  2.70Mw │   2.13kw │   2.13kw │     91.92% │
│ fa'(t1) │   8.20ms │  3.00Mw │   4.27kw │   4.27kw │     97.07% │
│ fa(t1)  │   8.33ms │  2.85Mw │   2.74kw │   2.74kw │     98.52% │
│ fa'(t2) │   7.57ms │  2.77Mw │   2.70kw │   2.70kw │     89.54% │
│ fa(t2)  │   7.90ms │  2.72Mw │   2.25kw │   2.25kw │     93.41% │
│ fa'(t3) │   8.25ms │  3.00Mw │   4.22kw │   4.22kw │     97.62% │
│ fa(t3)  │   8.45ms │  2.89Mw │   2.83kw │   2.83kw │    100.00% │
│ fa'(t4) │   7.72ms │  2.83Mw │   3.08kw │   3.08kw │     91.36% │
│ fa(t4)  │   7.99ms │  2.76Mw │   2.23kw │   2.23kw │     94.50% │
│ fa'(t5) │   7.45ms │  2.74Mw │   2.55kw │   2.55kw │     88.19% │
│ fa(t5)  │   7.91ms │  2.74Mw │   2.32kw │   2.32kw │     93.59% │
│ fa'(t6) │   8.02ms │  2.94Mw │   3.75kw │   3.75kw │     94.95% │
│ fa(t6)  │   8.42ms │  2.87Mw │   2.74kw │   2.74kw │     99.67% │
│ fa'(t7) │   7.95ms │  2.91Mw │   3.58kw │   3.58kw │     94.06% │
│ fa(t7)  │   8.30ms │  2.87Mw │   2.60kw │   2.60kw │     98.24% │
│ fa'(t8) │   7.53ms │  2.77Mw │   2.52kw │   2.52kw │     89.09% │
│ fa(t8)  │   7.86ms │  2.73Mw │   2.29kw │   2.29kw │     92.95% │
│ fa'(t9) │   7.66ms │  2.82Mw │   2.87kw │   2.87kw │     90.63% │
│ fa(t9)  │   8.03ms │  2.79Mw │   2.59kw │   2.59kw │     95.04% │
└─────────┴──────────┴─────────┴──────────┴──────────┴────────────┘