pub fn metadata_of<R: Read + Seek>(reader: R) -> Result<DocumentMut>Expand description
The metadata document of a byte stream, asking no conformance question.
Reads the member SPEC 2.1 names and parses it, requiring of that member what SPEC 2.2 requires: one of it, valid TOML, UTF-8. It looks for neither required key and never locates a payload.
This exists because a container can be non-conformant somewhere else
entirely and still carry a metadata document worth reading: payload.file
naming no member, naming several, or naming something SPEC 2.3 forbids all
leave a document that parsed cleanly, and Container::read returns an
error over the payload before a caller can reach it. A program showing a
person what is in a file wants to show them that document.
It is not a verdict and must not be used as one: a document coming back
says nothing about whether the container conforms. Ask
validate for that, which is the only function here that
answers the question SPEC 3 constrains.