Add pauseIf() / pauseUnless() (#999)

* Add `pauseIf()`

* Add `pauseUnless()`

Author: u01jmg3

src/Browser.php

@@ -635,6 +635,38 @@ public function pause($milliseconds)
         return $this;
     }
 
+    /**
+     * Pause for the given amount of milliseconds if the given condition is true.
+     *
+     * @param  bool  $boolean
+     * @param  int  $milliseconds
+     * @return $this
+     */
+    public function pauseIf($boolean, $milliseconds)
+    {
+        if ($boolean) {
+            return $this->pause($milliseconds);
+        }
+
+        return $this;
+    }
+
+    /**
+     * Pause for the given amount of milliseconds unless the given condition is true.
+     *
+     * @param  bool  $boolean
+     * @param  int  $milliseconds
+     * @return $this
+     */
+    public function pauseUnless($boolean, $milliseconds)
+    {
+        if (! $boolean) {
+            return $this->pause($milliseconds);
+        }
+
+        return $this;
+    }
+
     /**
      * Close the browser.
      *