Err creates a new Error.

file already closed.

file already exists.

process file desciptor limit reached.

read/write IO error.

file lock failed.

no space or quota exhausted.

file does not exist.

operation not supported.

unknown OS error.

permission denied.

cannot resolve path.

file unlock failed.

SyncDataOnly will only flush the file data, without enforcing an update on the file metadata (like file size or modification time).

Error is the common error type used by vfs implementations.

Kind encodes an error code for use by applications.