You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: tag.rs
    path of file: ./repos/ruffle/flv/src
    
    the code of the file until where you have to start completion: use crate::error::Error;
use crate::reader::FlvReader;
use crate::script::ScriptData;
use crate::sound::AudioData;
use crate::video::VideoData;

use std::io::{Seek, SeekFrom};

#[repr(u8)]
#[derive(PartialEq, Debug, Clone)]
pub enum TagData<'a> {
    Audio(AudioData<'a>) = 8,
    Video(VideoData<'a>) = 9,
    Script(ScriptData<'a>) = 18,

   
    
    pub fn skip_back(reader: &mut FlvReader<'a>) -> Result<(), Error> {
        let previous_tag_size = reader.read_u32()?;

        if previous_tag_size == 0 {
            // We have to stay in a valid end position but we can't seek back
            // any further, so we un-read the prior u32
            reader.seek(SeekFrom::Current(-4))?;
            Err(Error::EndOfData)
        } else {
            // NOTE: We need to seek back an extra 4 bytes for the u32 we just
            // read, which gets us to the start of the next tag. Then we need
            // to skip back another 4 bytes for the prior tag's back tag so
            // that we're in a valid position for another `parse`/`skip_back`.
            reader.seek(SeekFrom::Current(-(previous_tag_size as i64) - 8))?;
            Ok(())
        }
    }