[timggggggg]

Description

Prepare all standard library function calls at startup, precomputing argument layouts and defaults to reduce per-event lookups and allocations.

Preserve existing semantics and concurrency safety, with regression tests and benchmarks to validate correctness and performance.

Before #1028

Branch: 1033-expand-transform-benchmark-coverage. Commit: 4d1fcc3.

Scenario	Variant	ns/op	B/op	allocs/op
assign_new5	transform	445.4	312	9
assign_new5	modify	148.6 (-66.6%)	0 (-100.0%)	0 (-100.0%)
trim4	transform	1440	2352	33
trim4	modify	101.9 (-92.9%)	0 (-100.0%)	0 (-100.0%)
rename/preserve/5	transform	2212	1352	43
rename/preserve/5	rename	373.3 (-83.1%)	0 (-100.0%)	0 (-100.0%)
logs/no_regex/mixed	transform	2782	3536	63
logs/no_regex/mixed	modify	2922 (+5.0%)	687 (-80.6%)	0 (-100.0%)
logs/regex/mixed	transform	16307	1864	35
logs/regex/mixed	modify	92907 (+469.7%)	2250 (+20.7%)	12 (-65.7%)
chains/mapping/16/mixed	transform	589.3	744	15
chains/mapping/16/mixed	modify_x16	319.5 (-45.8%)	0 (-100.0%)	0 (-100.0%)
chains/tags/16/mixed	transform	3820	3724	110
chains/tags/16/mixed	modify_x16	478.7 (-87.5%)	0 (-100.0%)	0 (-100.0%)
dynamic/trim_slice/mixed	transform	2756	5774	27
collections/filter_sum/64	transform	35502	50912	556

After #1028

Branch: 1028-transform-prepare-function-calls. Commit: 9fad910
(includes the merged benchmark branch).

Scenario	Variant	ns/op	B/op	allocs/op
assign_new5	transform	433.6	312	9
assign_new5	modify	147.5 (-66.0%)	0 (-100.0%)	0 (-100.0%)
trim4	transform	595.4	752	17
trim4	modify	102.7 (-82.8%)	0 (-100.0%)	0 (-100.0%)
rename/preserve/5	transform	2206	1352	43
rename/preserve/5	rename	372.4 (-83.1%)	0 (-100.0%)	0 (-100.0%)
logs/no_regex/mixed	transform	1294	944	35
logs/no_regex/mixed	modify	2814 (+117.5%)	686 (-27.3%)	0 (-100.0%)
logs/regex/mixed	transform	15438	1480	31
logs/regex/mixed	modify	86761 (+462.0%)	2234 (+50.9%)	12 (-61.3%)
chains/mapping/16/mixed	transform	375.7	360	11
chains/mapping/16/mixed	modify_x16	296.5 (-21.1%)	0 (-100.0%)	0 (-100.0%)
chains/tags/16/mixed	transform	3543	3724	110
chains/tags/16/mixed	modify_x16	481.9 (-86.4%)	0 (-100.0%)	0 (-100.0%)
dynamic/trim_slice/mixed	transform	2135	4702	18
collections/filter_sum/64	transform	36641	50912	556

Conclusion

The percentages below compare transform after #1028 with transform before #1028,
using (after - before) / before * 100.

Preparing function calls in #1028 reduced allocation overhead in the function-call workloads. The largest
observed reductions in ns/op were in nested trim calls and regex-free log parsing:

• trim4: -58.7% ns/op, -68.0% B/op, -48.5% allocs/op.
• logs/no_regex/mixed: -53.5% ns/op, -73.3% B/op, -44.4% allocs/op.
• chains/mapping/16/mixed: -36.2% ns/op, -51.6% B/op, -26.7% allocs/op.
• dynamic/trim_slice/mixed: -22.5% ns/op, -18.6% B/op, -33.3% allocs/op.
• logs/regex/mixed: -5.3% ns/op, -20.6% B/op, -11.4% allocs/op.

Fixes #1028