But we can't just replace `remains` with `enqueued` there, because lets say if there is a gem called `foo` which has dependency on `bar` and `baz` and `bar` and `baz` are yet to be installed and hence have entries in `remains` hash. We can install `foo` only if `bar` and `baz` are NOT there in `remains` hash (https://github.com/bundler/bundler/pull/2816/files)