Returns the value of :json_library option, which specifies the module for JSON encoding.

To customize the JSON module, including the following in your config/config.exs:

config :combo, :json_library, JSON

Returns the value of :plug_init_mode option that controls when plugs are initialized.

It's recommended to set it to :runtime in development for compilation time improvements. It must be :compile in production (the default).

This option is passed as the :init_mode to Plug.Builder.compile/3.