fn next(&mut self) -> Option<Self::Item> {
        if self.cache.is_empty() && self.next.is_some() {
            if let Err(err) = self.reload_cache() {
                return Some(Err(err));
            }
        };
        self.cache.pop_front().map(Ok)
    }
/// Return the next item from the cache, if the cache is empty reload it.
Return the next item from the cache, if the cache is empty reload it.
Return the next item from the cache if the cache is empty reload it .
fn next(&mut self) -> Option<Self::Item> {
        if self.cache.is_empty() && self.next.is_some() {
            if let Err(err) = self.reload_cache() {
                return Some(Err(err));
            }
        };
        self.cache.pop_front().map(Ok)
    }
fn next ( & mut self ) -> Option < Self :: Item > { if self . cache . is_empty ( ) && self . next . is_some ( ) { if let Err ( err ) = self . reload_cache ( ) { return Some ( Err ( err ) ) ; } } ; self . cache . pop_front ( ) . map ( Ok ) }
Return the next item from the cache, if the cache is empty reload it.
Return the next item from the cache if the cache is empty reload it .
&mut self
&mut self