// Package retry provides configurable HTTP request retry as client middleware.
//
// The retry middleware wraps an http.RoundTripper and automatically retries
// failed requests based on a configurable policy, with exponential backoff
// and optional jitter.
//
// # Usage
//
//	mw := retry.Transport(
//	    retry.WithMaxAttempts(3),
//	    retry.WithBackoff(retry.ExponentialBackoff(100*time.Millisecond, 5*time.Second)),
//	)
//	transport := mw(http.DefaultTransport)
//
// # Retry-After
//
// The retry middleware respects the Retry-After response header. If a server
// returns 429 or 503 with Retry-After, the delay from the header overrides
// the backoff strategy.
//
// # Request bodies
//
// For requests with bodies to be retried, the request must have GetBody set.
// Use httpx.NewJSONRequest or httpx.NewFormRequest which set GetBody
// automatically.
//
// # Sentinel errors
//
// ErrRetryExhausted is returned when all attempts fail. The original error
// is wrapped and accessible via errors.Unwrap.
package retry