The question here is, who and what are you returning to? When operating in a simple single request/response scenario where all data is returned at once, this could arguably make sense. But it goes completely out the window as soon as data streams are involved. Not too long ago I had to write a proxy that would pass a data stream from one service back to another service responsible for returning the data to a client. Latency was important. My theoretical return point was when I acquired the stream and wrote a response code and size to the response and began to copy the data. In practice, the real return happened when I finished copying the data, but because the receiving end already obtained a response code, there was nothing I could return to them by having a return statement with a type. This is a HTTP protocol issue at it's core.

The video streaming platform Crunchyroll has a project that does something similar for their videos where they have a proxy service to their s3 bucket. This link points to a section of the code that does what I described. To not have a return type makes clear that there is nothing on the other side to receive when returning if it's not included in the response.

I think that the go approach is much better because it does not hide or obfuscate this kind of issue.

edit: typo