SendStream is a TStream property that represents the destination for data sent in the logging intercept. 

Applications must assign a TStream instance to the SendStream property to allow logging for data sent in the logging intercept. 

Set FreeStreams to True if the stream instance can be freed when Disconnect is called for the logging intercept. 

When the intercept is Active, data sent by the logging intercept is written to SendStream. No textual messages or date / timestamp values are written to SendStream. 

Use ReceiveStream to indicate the stream used for writing data received on the logging intercept.

TIdLogStream.FreeStreams 

TIdLogStream.ReceiveStream