JSON pretty printing indentation using tabs or double spaces

Description

The current indentation of pretty printed JSON with json_encode() is using 4 bytes per level.
I feel we are lacking the ability to choose intendation type, i.e. for optimization.

Example:

• Tab (1 bytes)
• Two spaces (2 bytes)
• Four spaces (4 bytes)

Maybe by setting a flag to either:
JSON_PRETTY_PRINT
JSON_PRETTY_PRINT_TABS
JSON_PRETTY_PRINT_DOUBLE_SPACES

I know that we can preg_replace() it the way we want. But why waste resources if we could have it at the core.