fn len(&self) -> Option<u64> {
        match self.metadata() {
            Ok(metadata) => Some(metadata.len()),
            _ => None,
        }
    }
/// Returns the length in bytes of the `std::io::File` backing the `MediaSource`.
///
/// Note: This operation involves querying the underlying file descriptor for information and
/// may be moderately expensive. Therefore it is recommended to cache this value if used often.
Returns the length in bytes of the `std::io::File` backing the `MediaSource`.
Note: This operation involves querying the underlying file descriptor for information and
may be moderately expensive. Therefore it is recommended to cache this value if used often.
Returns the length in bytes of the ` std :: io :: File ` backing the ` MediaSource ` . Note : This operation involves querying the underlying file descriptor for information and may be moderately expensive . Therefore it is recommended to cache this value if used often .
fn len(&self) -> Option<u64> {
        match self.metadata() {
            Ok(metadata) => Some(metadata.len()),
            _ => None,
        }
    }
fn len ( & self ) -> Option < u64 > { match self . metadata ( ) { Ok ( metadata ) => Some ( metadata . len ( ) ) , _ => None , } }
Returns the length in bytes of the `std::io::File` backing the `MediaSource`.
Returns the length in bytes of the ` std :: io :: File ` backing the ` MediaSource ` .
&self
&self