getBreakpoint method
Get the current breakpoint based on screen width
Implementation
FSBreakpoint getBreakpoint(double screenWidth) {
if (screenWidth < xs) return FSBreakpoint.xs;
if (screenWidth < sm) return FSBreakpoint.sm;
if (screenWidth < md) return FSBreakpoint.md;
if (screenWidth < lg) return FSBreakpoint.lg;
if (screenWidth < xl) return FSBreakpoint.xl;
return FSBreakpoint.xxl;
}