pub fn from_buf(
    rd: &mut dyn BufRead,
) -> Result<Option<(SectionKind, Vec<u8>)>, Error>Expand description
Extract and decode the next supported PEM section from rd.
- Ok(None) is returned if there is no PEM section read from rd.
- Underlying IO errors produce a Err(...)
- Otherwise each decoded section is returned with a Ok(Some(...))