81235 Migrate to ChannelBuffers.push (a: tests, team, framework, f: material design, a: accessibility, cla: yes, f: cupertino, d: examples, waiting for tree to go green)

81278 Assert for valid ScrollController in Scrollbar gestures (framework, f: scrolling, cla: yes, f: cupertino, a: quality, waiting for tree to go green, a: error message)

81406 Add trailing commas in examples and packages/flutter/ (team, framework, f: material design, cla: yes, f: cupertino, d: examples)

81578 Enable library_private_types_in_public_api lint (a: tests, team, tool, framework, f: material design, a: accessibility, cla: yes, f: cupertino, d: examples, waiting for tree to go green)