private static function get_vendor_dir() {
		static $vendor_dir = null;

		if ( null !== $vendor_dir ) {
			return $vendor_dir;
		}

		$paths = [
			dirname( dirname( dirname( dirname( __DIR__ ) ) ) ) . '/bin/wp',
			dirname( dirname( dirname( dirname( dirname( __DIR__ ) ) ) ) ) . '/bin/wp',
			dirname( dirname( __DIR__ ) ) . '/vendor/bin/wp',
		];

		foreach ( $paths as $path ) {
			if ( file_exists( $path ) && is_executable( $path ) ) {
				$vendor_dir = (string) realpath( dirname( $path ) );
				break;
			}
		}

		if ( null === $vendor_dir ) {
			// Did not detect WP-CLI binary, so make a random guess.
			$vendor_dir = '/usr/local/bin';
		}

		return $vendor_dir;
	}