Response has already been sent

[Miha-x64]

Similar to PHP's 'headers already sent by' :)
Can be reproduces by something like

div {
    p()
    classes += "whatever
}

Stack trace contains no my functions, only host's, coroutines', ktor's, etc.

For absolute safety such constructs should be prohibited. For example, DSL function can accept two functions. One will work with attributes, other — with content, and second must be evaluated after first.

[cy6erGn0m]

This would work well if there is DOM tag consumer: in this case the following works well. Same for React builder. So this is not a mistake that it is not prohibited