google-cloud-platform

Is your feature request related to a problem? Please describe.
Columns can only be resized by drag on the edges, but this is not an accessible method and is especially difficult on touch screens.

It can also be difficult to see where the click/drag target exactly is. MUI’s Data Grid is a good example of explicitly showing the drag target: https://mui.com/components/data-grid/columns/#resiz

This is motivated by #5703. Applications may need to persist the state of pagination iterators, for example, because they are implementing a web service that returns pages of results.

I suggested this API:

struct Page {
  std::vector<std::string> bucket_names;
  std::string reader_state;
};

Page BucketsPage(gcs::Client client, std::string reader_state) {
  auto reader = client.