TUN-6724: Migrate to sentry-go from raven-go

vendor/github.com/getsentry/sentry-go/internal/ratelimit/retry_after.go

@@ -0,0 +1,40 @@
+package ratelimit
+
+import (
+	"errors"
+	"strconv"
+	"time"
+)
+
+const defaultRetryAfter = 1 * time.Minute
+
+var errInvalidRetryAfter = errors.New("invalid input")
+
+// parseRetryAfter parses a string s as in the standard Retry-After HTTP header
+// and returns a deadline until when requests are rate limited and therefore new
+// requests should not be sent. The input may be either a date or a non-negative
+// integer number of seconds.
+//
+// See https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Retry-After
+//
+// parseRetryAfter always returns a usable deadline, even in case of an error.
+//
+// This is the original rate limiting mechanism used by Sentry, superseeded by
+// the X-Sentry-Rate-Limits response header.
+func parseRetryAfter(s string, now time.Time) (Deadline, error) {
+	if s == "" {
+		goto invalid
+	}
+	if n, err := strconv.Atoi(s); err == nil {
+		if n < 0 {
+			goto invalid
+		}
+		d := time.Duration(n) * time.Second
+		return Deadline(now.Add(d)), nil
+	}
+	if date, err := time.Parse(time.RFC1123, s); err == nil {
+		return Deadline(date), nil
+	}
+invalid:
+	return Deadline(now.Add(defaultRetryAfter)), errInvalidRetryAfter
+}