[Utils > Backoff] Remove as no longer used

src/utils/Backoff.js

@@ -1,41 +0,0 @@
-module.exports = class Backoff { // Internal library / utility for a class to retry a callback with delays, etc.
-  constructor(min = 500, max = (min * 10)) {
-    Object.assign(this, { min, max });
-    this.reset();
-    
-    this.pending = () => this._timeoutId != null; // If timeout currently set / waiting
-  }
-
-  fail(callback) { // On fail, wait and callback
-    this.current = Math.min(this.current + (this.current * 2), this.max);
-
-    this.fails++; // Bump fails
-
-    if (!callback) return this.current; // No callback given, skip rest of this
-    if (this._timeoutId != null) throw new Error(); // Timeout already set as waiting for another callback to call, throw error
-
-    this._timeoutId = setTimeout(() => { // Set new timeout
-      try {
-        callback(); // Run callback
-      } finally {
-        this._timeoutId = null; // Stop tracking timeout internally as it's been executed
-      }
-    }, this.current);
-
-    return this.current;
-  }
-
-  succeed() { // Reset and cancel
-    this.reset();
-    this.cancel();
-  }
-
-  cancel() { // Cancel current timeout
-    this._timeoutId = clearTimeout(this._timeoutId); // Stop timeout
-  }
-
-  reset() { // Reset internal state
-    this.current = this.min;
-    this.fails = 0;
-  }
-};