The section about the guarantees of read/write doesn't seem entirely correct to me. For sure it's relevant to why the data is there, but the reason it doesn't t

The section about the guarantees of read/write doesn't seem entirely correct to me. For sure it's relevant to why the data is there, but the reason it doesn't terminate is just because read doesn't tell you there's an eof until you try to read again past the end. It would be entirely possible to construct a version of this loop that would terminate. Though it would be awkward.