Pragmatic rate limiter for Binance REST APIs - optimized for regular trading, not HFT.

This implementation follows a reactive approach suitable for non-HFT usage:

• Monitors rate limit headers from responses and logs warnings
• Does NOT maintain sliding windows or complex state
• Relies on Req's retry mechanism for 429 responses
• Emergency Bypass: Always allows critical safety operations (cancel_order, cancel_all, close_position)
• Reserved Capacity: Reserves 10% of rate limit capacity for emergency operations

Binance Rate Limits (per minute)

• Spot API: 1200 weight units (1080 regular, 120 emergency reserve)
• SAPI: 12000 weight units (10800 regular, 1200 emergency reserve)
• USD-M Futures: 2400 weight units (2160 regular, 240 emergency reserve)
• COIN-M Futures: 2400 weight units (2160 regular, 240 emergency reserve)
• Portfolio Margin: 3000 weight units (2700 regular, 300 emergency reserve)

Emergency Operations

Emergency operations that bypass normal rate limits:

• Order cancellation (single, batch, all)
• Position closing
• Risk management operations

Monitoring Approach

• Logs WARNING at 80% of regular capacity
• Logs CRITICAL at 95% of regular capacity
• Emergency operations always proceed even at 100% usage
• Lets Req handle 429 responses with exponential backoff

ETS Table Management

This module creates separate ETS tables for each API type to prevent contention:

• Table naming convention: Elixir.ZenCex.Adapters.Binance.RateLimiter.Table.{api_type}
• Tables are created on-demand when first accessed
• Supported API types: :spot, :sapi, :usdm_futures, :coinm_futures, :portfolio
• Each table tracks rate limit usage independently with minute-based windows