Use matterbridge vendored slack

vendor/github.com/nlopes/slack/backoff.go

@@ -1,57 +0,0 @@
-package slack
-
-import (
-	"math"
-	"math/rand"
-	"time"
-)
-
-// This one was ripped from https://github.com/jpillora/backoff/blob/master/backoff.go
-
-// Backoff is a time.Duration counter. It starts at Min.  After every
-// call to Duration() it is multiplied by Factor.  It is capped at
-// Max. It returns to Min on every call to Reset().  Used in
-// conjunction with the time package.
-type backoff struct {
-	attempts int
-	//Factor is the multiplying factor for each increment step
-	Factor float64
-	//Jitter eases contention by randomizing backoff steps
-	Jitter bool
-	//Min and Max are the minimum and maximum values of the counter
-	Min, Max time.Duration
-}
-
-// Returns the current value of the counter and then multiplies it
-// Factor
-func (b *backoff) Duration() time.Duration {
-	//Zero-values are nonsensical, so we use
-	//them to apply defaults
-	if b.Min == 0 {
-		b.Min = 100 * time.Millisecond
-	}
-	if b.Max == 0 {
-		b.Max = 10 * time.Second
-	}
-	if b.Factor == 0 {
-		b.Factor = 2
-	}
-	//calculate this duration
-	dur := float64(b.Min) * math.Pow(b.Factor, float64(b.attempts))
-	if b.Jitter == true {
-		dur = rand.Float64()*(dur-float64(b.Min)) + float64(b.Min)
-	}
-	//cap!
-	if dur > float64(b.Max) {
-		return b.Max
-	}
-	//bump attempts count
-	b.attempts++
-	//return as a time.Duration
-	return time.Duration(dur)
-}
-
-//Resets the current value of the counter back to Min
-func (b *backoff) Reset() {
-	b.attempts = 0
-}