src/Flash.php
public function delete(string $key): self
    {
        unset($this->data[$key]);
        unset($this->session[$key]);
        return $this;
    }
public function delete(string $key): self
    {
        unset($this->data[$key]);
        unset($this->session[$key]);
        return $this;
    }
Remove specified key

@param string $key Key
@return  Flash