The mixed `number | bigint` representation was useful optimization for
pointers. Now, pointers are represented as V8 externals. As part of the
FFI stabilization effort we want to make `bigint` the only
representation for `u64` and `i64`.
BigInt representation performance is almost on par with mixed
representation with the added benefit that its less confusing and users
don't need manual checks and conversions for doing operations on the
value.
```
cpu: AMD Ryzen 5 7530U with Radeon Graphics
runtime: deno 1.43.6+92a8d09 (x86_64-unknown-linux-gnu)
file:///home/divy/gh/ffi/main.ts
benchmark time (avg) iter/s (min … max) p75 p99 p995
-------------------------------------------------------------------------- -----------------------------
nop 4.01 ns/iter 249,533,690.5 (3.97 ns … 10.8 ns) 3.97 ns 4.36 ns 9.03 ns
ret bigint 7.74 ns/iter 129,127,186.8 (7.72 ns … 10.46 ns) 7.72 ns 8.11 ns 8.82 ns
ret i32 7.81 ns/iter 128,087,100.5 (7.77 ns … 12.72 ns) 7.78 ns 8.57 ns 9.75 ns
ret bigint (add op) 15.02 ns/iter 66,588,253.2 (14.64 ns … 24.99 ns) 14.76 ns 19.13 ns 19.44 ns
ret i32 (add op) 12.02 ns/iter 83,209,131.8 (11.95 ns … 18.18 ns) 11.98 ns 13.11 ns 14.5 ns
```
1. Generally we should prefer to use the `log` crate.
2. I very often accidentally commit `eprintln`s.
When we should use `println` or `eprintln`, it's not too bad to be a bit
more verbose and ignore the lint rule.
