buffer: use for loop for small copy length
02:04:12 buffers/buffer-copy.js n=5000000 partial='true' bytes=0 -0.95 % ±1.11% ±1.47% ±1.93%
02:04:12 buffers/buffer-copy.js n=5000000 partial='true' bytes=128 -0.47 % ±0.59% ±0.79% ±1.03%
02:04:12 buffers/buffer-copy.js n=5000000 partial='true' bytes=16 *** 185.54 % ±0.86% ±1.15% ±1.50%
02:04:12 buffers/buffer-copy.js n=5000000 partial='true' bytes=32 *** 91.02 % ±0.64% ±0.85% ±1.11%
02:04:12 buffers/buffer-copy.js n=5000000 partial='true' bytes=32768 ** 15.03 % ±8.49% ±11.40% ±15.06%
02:04:12 buffers/buffer-copy.js n=5000000 partial='true' bytes=64 -0.72 % ±0.75% ±0.99% ±1.29%
02:04:12 buffers/buffer-copy.js n=5000000 partial='true' bytes=8 *** 278.69 % ±1.22% ±1.64% ±2.16%