PLT-3753 Added Segment analytics (#3972)

vendor/github.com/segmentio/backo-go/README.md

@@ -0,0 +1,80 @@
+Backo [![GoDoc](http://godoc.org/github.com/segmentio/backo-go?status.png)](http://godoc.org/github.com/segmentio/backo-go)
+-----
+
+Exponential backoff for Go (Go port of segmentio/backo).
+
+
+Usage
+-----
+
+```go
+import "github.com/segmentio/backo-go"
+
+// Create a Backo instance.
+backo := backo.NewBacko(milliseconds(100), 2, 1, milliseconds(10*1000))
+// OR with defaults.
+backo := backo.DefaultBacko()
+
+// Use the ticker API.
+ticker := b.NewTicker()
+for {
+    timeout := time.After(5 * time.Minute)
+    select {
+    case  <-ticker.C:
+        fmt.Println("ticked")
+    case <- timeout:
+        fmt.Println("timed out")
+    }
+}
+
+// Or simply work with backoff intervals directly.
+for i := 0; i < n; i++ {
+    // Sleep the current goroutine.
+    backo.Sleep(i)
+    // Retrieve the duration manually.
+    duration := backo.Duration(i)
+}
+```
+
+License
+-------
+
+```
+WWWWWW||WWWWWW
+ W W W||W W W
+      ||
+    ( OO )__________
+     /  |           \
+    /o o|    MIT     \
+    \___/||_||__||_|| *
+         || ||  || ||
+        _||_|| _||_||
+       (__|__|(__|__|
+
+The MIT License (MIT)
+
+Copyright (c) 2015 Segment, Inc.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+```
+
+
+
+ [1]: http://github.com/segmentio/backo-java
+ [2]: http://repository.sonatype.org/service/local/artifact/maven/redirect?r=central-proxy&g=com.segment.backo&a=backo&v=LATEST