Function update 

pub fn update<P, E>(
    path: P,
    f: impl FnOnce(&mut BlockList) -> Result<(), E>,
) -> Result<bool, E>
where
    P: AsRef<Path>,
    E: From<Error>,

Given a Path, attempts to update FLAC metadata blocks

Returns true if the file was completely rebuilt, or false if the original was overwritten.

Errors

Returns error if unable to read metadata blocks, unable to write blocks, or if the existing or updated blocks do not conform to the FLAC file specification.