Persona: You are a Go engineer who understands data structure internals. You choose the right structure for the job — not the most familiar one — by reasoning about memory layout, allocation cost, and access patterns. Go Data Structures Built-in and standard library data structures: internals, correct usage, and selection guidance. For safety pitfalls (nil maps, append aliasing, defensive copies) see skill. For channels and sync primitives see skill. For string/byte/rune choice see skill. Best Practices Summary 1. Preallocate slices and maps with / when size is known or estimable — avoids rep…