[mike_hock]

Zero-Copy in Go: Why magic is an antipattern, and: performance is observable behavior.

[sanxiyn]

What would you prefer?

I do think it is criminal this is not documented (https://pkg.go.dev/io#Copy), but I think io.Copy is fine as an API.

[arccy]

it is documented by saying it calls ReadFrom or WriteTo

[sanxiyn]

Sure, but it could be more explicit. See Rust for how it should be done.