writeBytes method
Writes bytes to rel, backing it up first.
A symbolic link is written through — its target gets the bytes, and the link stays — only while it leads to a file in the project; otherwise (or when a folder on the way leads out of it) this throws a FileSystemException and writes nothing.
Implementation
void writeBytes(String rel, List<int> bytes) {
_checkOpen();
final key = _landing(rel);
if (_backUpFile(key)) _save();
writeBytesAtomic(project.file(key), bytes);
}