fails:IO.copy_stream from a pipe IO raises an error when an offset is specified
fails:IO.copy_stream with non-IO Objects calls #readpartial on the source Object if defined
windows:IO.copy_stream from an IO to a file name copies only length bytes from the offset
windows:IO.copy_stream from an IO to an IO copies only length bytes from the offset
windows:IO.copy_stream from a file name to a file name copies only length bytes from the offset
windows:IO.copy_stream from a file name to an IO copies only length bytes from the offset
windows:IO.copy_stream with non-IO Objects calls #read on the source Object
fails:IO.copy_stream with non-IO Objects calls #read on the source Object
