NewFile returns a new go-fuse File instance.

NewFS returns a new encrypted FUSE overlay filesystem.

FALLOC_DEFAULT is a "normal" fallocate operation.

FALLOC_FL_KEEP_SIZE allocates disk space while not modifying the file size.

Args is a container for arguments that are passed from main() to fusefrontend.

File - based on loopbackFile in go-fuse/fuse/nodefs/files.go.

FS implements the go-fuse virtual filesystem interface.