Write a performance optimization guide for {{focus_area}} in {{language}} to achieve {{performance_goal}} in a {{tone}} tone for developers and engineers. Output as numbered steps with action titles, detailed instructions, expected outcomes, and pitfalls. Cover: measuring current performance, identifying bottlenecks, 10 optimization techniques ordered by impact, and validation methods. Include language-specific tips and performance budget setup. Max 1500 words. Skip any section if information is unknown.