This returns an EventReader which read events from a single (bin / relay) log file, with appropriate parser applied on each event. 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 is responsible for checking the log file magic marker, the binlog format version and all format description events within the stream. It is also responsible for setting the checksum size for non-FDE events.