Complex sentence: There are some circumstances in which this is a desirable characteristic (e.g. piping a file over SSH) in the case that all data is important and the reader's output does not need to be synchronised with the input.
Split into simpler sentences: There are some circumstances in which this is a desirable characteristic (e.g. piping a file over SSH). In the case that all data is important, and the reader's output does not need to be synchronised with the input.