How can I measure the UI thread frame time bottleneck in a Flutter ListView before optimizing?
In a Flutter application that displays a vertically scrolling ListView with over 2,000 custom widgets, each widget performs a moderate amount of layout and paint work. During profiling, the frame time frequently exceeds the 16 ms target, causing visible jank, but it is unclear whether the delay originates from the UI thread’s layout/paint phases or from the
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