Function read_header_info 

pub async fn read_header_info<R>(
    reader: &mut R,
    file_size: u64,
    header_size_hint: Option<u64>,
) -> Result<HeaderInfo, AvroError>
where
    R: AsyncFileReader,

Available on crate feature async only.

Reads the Avro file header (magic, metadata, sync marker) asynchronously from reader.

On success, returns the parsed HeaderInfo containing the header and its length in bytes.