1 files changed, 29 insertions, 0 deletions
diff --git a/crypto/src/util/io/BaseOutputStream.cs b/crypto/src/util/io/BaseOutputStream.cs
index 0fc8e9681..87a850c35 100644
--- a/crypto/src/util/io/BaseOutputStream.cs
+++ b/crypto/src/util/io/BaseOutputStream.cs
@@ -1,5 +1,7 @@
 using System;
 using System.IO;
+using System.Threading;
+using System.Threading.Tasks;
 
 namespace Org.BouncyCastle.Utilities.IO
 {
@@ -11,8 +13,14 @@ namespace Org.BouncyCastle.Utilities.IO
         public sealed override bool CanWrite { get { return true; } }
 
 #if NETCOREAPP2_0_OR_GREATER || NETSTANDARD2_1_OR_GREATER
+        // TODO[api] sealed
         public override void CopyTo(Stream destination, int bufferSize) { throw new NotSupportedException(); }
 #endif
+        // TODO[api] sealed
+        public override Task CopyToAsync(Stream destination, int bufferSize, CancellationToken cancellationToken)
+        {
+            throw new NotSupportedException();
+        }
         public override void Flush() {}
         public sealed override long Length { get { throw new NotSupportedException(); } }
         public sealed override long Position
@@ -23,6 +31,11 @@ namespace Org.BouncyCastle.Utilities.IO
         public sealed override int Read(byte[] buffer, int offset, int count) { throw new NotSupportedException(); }
 #if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER
         public sealed override int Read(Span<byte> buffer) { throw new NotSupportedException(); }
+        // TODO[api] sealed
+        public override ValueTask<int> ReadAsync(Memory<byte> buffer, CancellationToken cancellationToken = default)
+        {
+            throw new NotSupportedException();
+        }
 #endif
         public sealed override long Seek(long offset, SeekOrigin origin) { throw new NotSupportedException(); }
         public sealed override void SetLength(long value) { throw new NotSupportedException(); }
@@ -37,6 +50,22 @@ namespace Org.BouncyCastle.Utilities.IO
             }
         }
 
+#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER
+        public override void Write(ReadOnlySpan<byte> buffer)
+        {
+            int count = buffer.Length;
+            for (int i = 0; i < count; ++i)
+            {
+                WriteByte(buffer[i]);
+            }
+        }
+
+        public override ValueTask WriteAsync(ReadOnlyMemory<byte> buffer, CancellationToken cancellationToken = default)
+        {
+            return Streams.WriteAsync(this, buffer, cancellationToken);
+        }
+#endif
+
         public virtual void Write(params byte[] buffer)
         {
             Write(buffer, 0, buffer.Length);