Exact bytes the PBNode Data field adds for a UnixFS directory.
Directory-only: the type field is hardcoded to directory (2 bytes) and
the default mode is 0o755. Do not use for file nodes (different type
byte, different default mode 0o644).
For the common case (no mode, no mtime) this is always 4 bytes:
innerSize=2 [0x08,0x01], wrapper 1+1+2=4.
Exact bytes the PBNode Data field adds for a UnixFS directory.
Directory-only: the type field is hardcoded to directory (2 bytes) and the default mode is 0o755. Do not use for file nodes (different type byte, different default mode 0o644).
For the common case (no mode, no mtime) this is always 4 bytes: innerSize=2 [0x08,0x01], wrapper 1+1+2=4.