The logic uses a type assertion to safely verify if the value backing the provided io.Reader interface also implements the io.ReaderFrom interface. If it matches, then it will use the more efficient implementation
if rf, ok := dst.(ReaderFrom); ok {
return rf.ReadFrom(src)
}
> In Java for all its faults this wouldn’t happen because you’d be forced to implement all the interfaces.
I don't think I would go that far. In Java, many libraries make heavy use of the `instanceof` keyword, which is more or less the same as Go type assertions.
Yes, essentially duck typing. See https://github.com/golang/go/blob/65504872cbca64d77f45828409...
The logic uses a type assertion to safely verify if the value backing the provided io.Reader interface also implements the io.ReaderFrom interface. If it matches, then it will use the more efficient implementation
> In Java for all its faults this wouldn’t happen because you’d be forced to implement all the interfaces.I don't think I would go that far. In Java, many libraries make heavy use of the `instanceof` keyword, which is more or less the same as Go type assertions.