public static function add($key, $value, $config = 'default')
    {
        $pool = static::pool($config);
        if (is_resource($value)) {
            return false;
        }

        return $pool->add($key, $value);
    }
public static function add($key, $value, $config = 'default')
    {
        $pool = static::pool($config);
        if (is_resource($value)) {
            return false;
        }

        return $pool->add($key, $value);
    }
public static function add ( $ key , $ value , $ config = 'default' ) { $ pool = static :: pool ( $ config ) ; if ( is_resource ( $ value ) ) { return false ; } return $ pool -> add ( $ key , $ value ) ; }
Write data for key into a cache engine if it doesn't exist already.

### Usage:

Writing to the active cache config:

```
Cache::add('cached_data', $data);
```

Writing to a specific cache config:

```
Cache::add('cached_data', $data, 'long_term');
```

@param string $key Identifier for the data.
@param mixed $value Data to be cached - anything except a resource.
@param string $config Optional string configuration name to write to. Defaults to 'default'.
@return bool True if the data was successfully cached, false on failure.
Or if the key existed already.
Write data for key into a cache engine if it doesn t exist already .