Re: [PATCH v2 2/4] http: add exponential backoff without Retry-After

> From: Ravi Mistry <rmistry@google.com>
> 
> When a server returns HTTP 429 without a Retry-After header, Git waits
> the same fixed http.retryAfter delay on every retry. If that delay is
> short (e.g., 1s), Git burns through all of its retries in just a few
> seconds before a busy server can recover. If that delay is long, even a
> brief glitch has to wait a long time on the first retry.
> 
> Pass the 1-based retry attempt count to handle_rate_limit_retry() and
> double http.retryAfter on each subsequent retry (1s, 2s, 4s, ..., via
> http.retryAfter * 2^(attempt - 1)), clamping the delay at
> http.maxRetryTime. This keeps the first retry fast while giving the
> server more time to recover on later attempts, matching curl's own
> --retry behavior (while keeping http.retryAfter's existing default of 0
> for immediate retries when unconfigured). When the server provides an
> explicit Retry-After header, continue to honor the server-provided delay
> (or fail fast if it exceeds http.maxRetryTime).