Private.DynamicSourceThis library allows for "dynamic" use of the CSS Constructed Stylesheet API. It is more powerful than inline_css, but can be much less performant.
Tl;dr: you should try as hard as possible for the input to attr to be a constant, not a string Value.t.
inline_css registers the provided string as a constructed stylesheet as a side effect. It will never change or remove the string.
In contrast, this library's produces a Vdom.Attr.t, which will also remove the stylesheet when it is removed from the DOM, and will update the stylesheet whenever the provided string changes, e.g. if the attr is produced by a Bonsai Value.t. Every such update will trigger a browser style recomputation, which can be very expensive if many DOM elements are affected.