public static File checkedMkdir(File dir) throws IOException {
		if (!createDir(dir)) {
			throw new IOException("Failed to create directory " + dir);
		}
		return dir;
	}
Ensures the specified leaf directory exists.
<p>
Throws an {@link IOException} if there is any problem while creating the directory.
<p>
Does not create any missing parent directories.  See {@link #checkedMkdirs(File)} instead.
<p>
Takes into account race conditions with external threads/processes
creating the same directory at the same time.

@param dir The directory to create.
@return a reference to the same {@link File} instance that was passed in.
@throws IOException if there was a failure when creating the directory (ie. the
parent directory did not exist or other issue).
Ghidra/Framework/Utility/src/main/java/utilities/util/FileUtilities.java