speed up the mutable vector append. measured on filter, I see 20% speedup at n=200, over 2.4x faster at n=10000
speed up the mutable vector append. measured on filter, I see 20% speedup at n=200, over 2.4x faster at n=10000

emmanueltouzery/prelude.ts,emmanueltouzery/prelude.ts,emmanueltouzery/prelude.ts