class function IsEndMarker(
    const ALine: string
): Boolean; override;

Boolean - True the line does not contain a continuation response.

IsEndMarker is an overridden Boolean class function used to indicate when the RFC-compliant protocol response contains a terminal response instead of a continuation response. 

IsEndMarker examines the value in ALine to determine if it contains a continuation mark for the protocol response. 

IsEndMarker returns True when ALine contains at least 4 characters and the fourth character is not the continuation marker character '-' (Decimal 45).