Precompile some functions for faster TTFX

[Tortar]

This has not a big impact but it works, e.g. now

julia> using Accessors

julia> struct Q k::Float64 end

julia> q = Q(1.0)
Q(1.0)

julia> @time @eval f(q) = @set q.k = 2.0;
  0.007665 seconds (2.08 k allocations: 161.078 KiB, 91.12% compilation time) # this pr
  0.021409 seconds (14.66 k allocations: 1023.523 KiB, 96.41% compilation time) # master

julia> @time @eval f(q);
  0.032977 seconds (23.63 k allocations: 1.616 MiB, 99.53% compilation time) # this pr
  0.032714 seconds (23.67 k allocations: 1.628 MiB, 99.52% compilation time) # master

Addresses partially #173

[Tortar]

I guess that the time spent on function definitions is anyway happening at precompile time inside packages though, but the precompile statements in this pr are practically zero cost so I think that they could be added nonetheless.

[Tortar]

hi @aplavin what do you think of this PR?

[aplavin]

Idk, we can add this I guess, what do you think @jw3126?
The gain is just ~15 ms, right? So Accessors is already quite good in ttfx :)

[jw3126]

Mhh the gain is minor, I wonder if it is worth the additional dependency. How does this impact precompile time?

[Tortar]

almost the same for precompile times (maybe 0.1 second more), but actually the additional dependency impacts a bit the importing:

julia> @time using Accessors
  0.039866 seconds (36.46 k allocations: 4.357 MiB, 10.73% compilation time) # this pr
  0.031610 seconds (25.88 k allocations: 3.539 MiB, 13.73% compilation time) # master

julia> struct Q k::Float64 end

julia> q = Q(1.0)
Q(1.0)

julia> @time @eval f(q) = @set q.k = 2.0;
  0.008145 seconds (2.08 k allocations: 144.578 KiB, 88.98% compilation time) # this pr
  0.022843 seconds (14.67 k allocations: 1.015 MiB, 95.64% compilation time) # master

julia> @time f(q);
  0.034677 seconds (23.59 k allocations: 1.614 MiB, 99.95% compilation time) # this pr
  0.034935 seconds (23.64 k allocations: 1.632 MiB, 99.93% compilation time) # master

so I close for now, let me know if you think it's still worth it

[jw3126]

Thanks @Tortar for experimenting with this.