This returns an EventReader which read and parses events from a (bin /relay) log stream composed of multiple log files. If no parser is available for the event, or if an error occurs during parsing, then the reader will return the original event along with the error. NOTE: this reader will transparently switch log files on rotate events (relay log wrapper events are not returned). When the reader fails to open a log file, it will return a *FailedToOpenFileError; it is safe to retry reading, assuming the filename is valid. When the reader encounters an invalid rotate event, it will return both the rotate event and an *InvalidRotationError.