core/release-notes/5.0/api-diff/netstandard2.1/5.0_System.Buffers.md

System.Buffers

 namespace System.Buffers {
     public readonly struct ReadOnlySequence<T> {
+        public long GetOffset(SequencePosition position);
     }
     public ref struct SequenceReader<T> where T : struct, IEquatable<T> {
+        public ReadOnlySequence<T> UnreadSequence { get; }
+        public void AdvanceToEnd();
+        public bool TryPeek(long offset, out T value);
+        public bool TryReadTo(out ReadOnlySpan<T> span, ReadOnlySpan<T> delimiter, bool advancePastDelimiter = true);
     }
 }