file(path, callback) {
        // Send file from local cache pool if available
        if (FilePool[path]) return this._send_file(FilePool[path], callback);

        // Create new LiveFile instance in local cache pool for new file path
        FilePool[path] = new LiveFile({
            path,
        });

        // Assign error handler to live file
        FilePool[path].on('error', (error) => this.throw(error));

        // Serve file as response
        this._send_file(FilePool[path], callback);
    }
This method is an alias of send() method except it sends the file at specified path.
This method automatically writes the appropriate content-type header if one has not been specified yet.
This method also maintains its own cache pool in memory allowing for fast performance.
Avoid using this method to a send a large file as it will be kept in memory.

@param {String} path
@param {function(Object):void=} callback Executed after file has been served with the parameter being the cache pool.