src/Framework/Application.php
public function boot()
    {
        if (!$this->booted) {
            foreach ($this->providers as $provider) {
                $provider->boot($this);
            }
        }

        $this->booted = true;
    }
public function boot()
    {
        if (!$this->booted) {
            foreach ($this->providers as $provider) {
                $provider->boot($this);
            }
        }

        $this->booted = true;
    }
Boots all providers

@return bool