anchor.diff:  %% Check that `RootDirectory++"/"++RelPath` is a re file.
   %% Return `false` if filesystem errors or timeouts were encountered.
   %%
  -%% In contrast to {@link filelib:is_regular/1} this function will not
  -%% clog the file I/O of other `file` or `filelib` operations in case
  -%% the underlying `stat` operation blocks.
  +%% The non-functional behaviour regarding safe access to directories is the same
  +%% as in {@link can_stat/2}.
   %%
  -%% For example, if an NFS mount is located at "/mnt/nfs" and a file
  -%% "/mnt/nfs/user-provided/a76f7e62" is expected to be a regular file
  -%% then `safeio:is_regular("/mnt/nfs", "user-provided/a76f7e62")`
  -%% will be a safe way to determine if the file is a regular file and
  -%% even if the NFS mount is stale, this function returns after a short
  -%% timeout.
  -%%
  -%% Also, subsequent calls to the `is regular` will immediately return
  -%% `false` if a check for "/mnt/nfs", that was initiated by previous
  -%% invokation, has not returned yet.
  -%% This mechanism works by starting an internal server for each distinct
  -%% `RootDirectory`.
   %% @end
   %%------------------------------------------------------------------------------
   -spec is_regular(file:filename(), file:filename(), timeout()) -> boolean().
  
positive.code: 
  %%------------------------------------------------------------------------------
  %% @doc
  %% Check that `Path` is an accessable path, e.g. a directory to a network
  %% mounted file system, that might be blocked due to network problems.
  %% @see can_state/2
  %% @end
  %% ------------------------------------------------------------------------------
  -spec can_stat(file:filename()) -> boolean().
  
negative.code: 
  %%------------------------------------------------------------------------------
  %% @doc
  %% Return true if calling `stat` on `Path` was successful.
  %%
  %% This function will not cause `file` or `filelib` operations to block, in case
  %% the underlying `stat` operation blocks. This is in contrast to `file` and
  %% `filelib` behaviour, where `filelib:is_regular/1` on a path that is in a
  %% stale NFS mount will cause other `filelib:...` operations on totally
  %% unrelated paths to block, too.
  %%
  %% Also, subsequent invocations will immediately return `false` if a check
  %% for `Path`, that was initiated by previous invocation, has not returned yet.
  %%
  %% This mechanism works by starting an internal server for each distinct `Path`,
  %% see {@link info/1}.
  %%
  %% @end
  %% ------------------------------------------------------------------------------
  