Production Go code patterns covering error handling, concurrency, naming, testing, and performance.

• Comprehensive error handling guidance: return errors instead of panicking, use error wrapping with %w for inspection and %v for boundaries, join multiple errors with errors.Join, and handle errors once at the appropriate level
• Concurrency best practices: unbuffered or size-1 channels, document goroutine lifetimes, prefer errgroup.Group for concurrent operations, and use typed atomics from sync/atomic
• Naming conventions: MixedCaps always, consistent initialisms (URL not Url), short names for limited scope, one or two-letter receiver names, and avoid repeating package names in identifiers
• Testing patterns: table-driven tests with parallel execution, use go-cmp for comparisons, synctest for deterministic concurrent testing (Go 1.25+), and verify interface compliance at compile time
• Performance tips: preallocate slices and maps with known capacity, use strings.Builder for concatenation, prefer strconv over fmt, and leverage standard library slices and maps packages