/// <summary>
/// Remove old expired items from the cache
/// </summary>
/// <remarks>
/// </remarks>
private void FlushExpired()
{
// We don't attempt to flush items from the cache when it isn't full, otherwise this could result in a lot
// of wasted effort.
if (_cache.IsFull)
{
var keys = _cache.Keys;
foreach (var key in keys)
{
// if we can get the value from the cache but the target of the weak reference is no longer there
// then remove from the cache.
if (_cache.TryGetValue(key, out var weakReference) && !weakReference.TryGetTarget(out var primitive))
{
_cache.Remove(key);
}
}
}
}