<PackageReference Include="NETStandard.Library" Version="2.0.0-preview2-25401-01" />

System.Text.RegularExpressions.GroupCollection

namespace System.Text.RegularExpressions { public class GroupCollection : ICollection, IEnumerable { public int Count { get; } public bool IsReadOnly { get; } public bool IsSynchronized { get; } public Group this[int groupnum] { get; } public Group this[string groupname] { get; } public object SyncRoot { get; } public void CopyTo(Array array, int arrayIndex); public IEnumerator GetEnumerator(); } }