Argument direction

• none - No direction
• in - Incoming direction
• out - Outgoing direction

enum @extern Eldbus.Introspection.Argument_Direction {
    none: 0,
    in,
    out
}

typedef enum {
    ELDBUS_INTROSPECTION_ARGUMENT_DIRECTION_NONE = 0,
    ELDBUS_INTROSPECTION_ARGUMENT_DIRECTION_IN,
    ELDBUS_INTROSPECTION_ARGUMENT_DIRECTION_OUT
} Eldbus_Introspection_Argument_Direction;