Layout.Sider has no ability to set breakpoint from custom string

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What problem does this feature solve?

If I want to make custom onBreakpoint event with size, which not included in default breakpoints { xs: '480px', sm: '576px', md: '768px', lg: '992px', xl: '1200px', xxl: '1600px', }

What does the proposed API look like?

breakpoint?: 'xs' | 'sm' | 'md' | 'lg' | 'xl' | 'xxl'; add custom string or, may be, number here