Use Buffer.allocUnsafe when available.

lodash.js

@@ -1470,6 +1470,7 @@
     var Buffer = moduleExports ? context.Buffer : undefined,
         Symbol = context.Symbol,
         Uint8Array = context.Uint8Array,
+        allocUnsafe = Buffer ? Buffer.allocUnsafe : undefined,
         defineProperty = Object.defineProperty,
         getPrototype = overArg(Object.getPrototypeOf, Object),
         iteratorSymbol = Symbol ? Symbol.iterator : undefined,
@@ -4424,7 +4425,9 @@
       if (isDeep) {
         return buffer.slice();
       }
-      var result = new buffer.constructor(buffer.length);
+      var length = buffer.length,
+          result = allocUnsafe ? allocUnsafe(length) : new buffer.constructor(length);
+
       buffer.copy(result);
       return result;
     }