Problem

Contentstack has a 10 requests/second rate limit. When using this SDK with Terraform (which makes concurrent requests), we constantly hit 429 errors that cause the whole operation to fail.

The SDK currently just returns "Unhandled StatusCode: 429" instead of handling these errors properly.

This is blocking our Terraform automation. Related issue: labd/terraform-provider-contentstack#3

What we need

1. Rate limiting - throttle requests to stay under the API limit
2. Retry logic - automatically retry 429 responses with backoff
3. Configuration options - let users adjust the limits

Suggested approach

Add these fields to ClientConfig:

RateLimit  float64  // requests per second, default 10
RateBurst  int      // burst size, default 10  
MaxRetries int      // retry attempts, default 3

When a 429 happens, wait and retry with exponential backoff (1s, 2s, 4s, etc).

Example usage

cfg := management.ClientConfig{
    BaseURL:    "https://api.contentstack.io",
    AuthToken:  "token",
    RateLimit:  8.0,  // be conservative
    MaxRetries: 3,
}

This would make the SDK much more reliable for automation tools like Terraform that need to make multiple concurrent requests.

Happy to contribute a PR if this sounds good!