Writes (overwriting existing) data at a seek, without changing seek.
n is number of bytes to actually write. default (0) is T.sizeof Will append to end of stream if at is outside stream
true if written successfully, false if not
See Implementation
Writes (overwriting existing) data at a seek, without changing seek.
n is number of bytes to actually write. default (0) is T.sizeof Will append to end of stream if at is outside stream