public ICollection <KeyValuePair <TPrimaryKey, TValue> > SecondaryKeyEntries(TSecondaryKey secondaryKey)
{
var result = ImmutableList.CreateBuilder <KeyValuePair <TPrimaryKey, TValue> >();
foreach (var entry in dictionary)
{
if (entry.Value.ContainsKey(secondaryKey))
{
foreach (var secondaryEntry in entry.Value)
{
result.Add(KeyValuePairs.Of(entry.Key, secondaryEntry.Value));
}
}
}
return(result.ToImmutable());
}