# System.Collections.Immutable

``` diff
 namespace System.Collections.Immutable {
     public readonly struct ImmutableArray<T> : ICollection, ICollection<T>, IEnumerable, IEnumerable<T>, IEquatable<ImmutableArray<T>>, IImmutableList<T>, IList, IList<T>, IReadOnlyCollection<T>, IReadOnlyList<T>, IStructuralComparable, IStructuralEquatable {
         public sealed class Builder : ICollection<T>, IEnumerable, IEnumerable<T>, IList<T>, IReadOnlyCollection<T>, IReadOnlyList<T> {
+            public ImmutableArray<T> DrainToImmutable();
         }
     }
 }
```

