Microsoft.Data.Sqlite: Add Span overloads to SqliteBlob

Fixes dotnet#16187

src/Microsoft.Data.Sqlite.Core/SqliteBlob.cs

@@ -167,6 +167,28 @@ public override int Read(byte[] buffer, int offset, int count)
                 throw new ArgumentException(Resources.InvalidOffsetAndCount);
             }
 
+            return Read(buffer.AsSpan(offset, count));
+        }
+
+        /// <summary>
+        ///     Reads a sequence of bytes from the current stream and advances the position within the stream by the
+        ///     number of bytes read.
+        /// </summary>
+        /// <param name="buffer">
+        ///     A region of memory. When this method returns, the contents of this region are replaced by the bytes read
+        ///     from the current source.
+        /// </param>
+        /// <returns>
+        ///     The total number of bytes read into the buffer. This can be less than the number of bytes allocated in
+        ///     the buffer if that many bytes are not currently available, or zero (0) if the end of the stream has been
+        ///     reached.
+        /// </returns>
+#if NET
+        public override int Read(Span<byte> buffer)
+#else
+        public virtual int Read(Span<byte> buffer)
+#endif
+        {
             if (_blob == null)
             {
                 throw new ObjectDisposedException(objectName: null);
@@ -178,12 +200,13 @@ public override int Read(byte[] buffer, int offset, int count)
                 position = Length;
             }
 
+            var count = buffer.Length;
             if (position + count > Length)
             {
                 count = (int)(Length - position);
             }
 
-            var rc = sqlite3_blob_read(_blob, buffer.AsSpan(offset, count), (int)position);
+            var rc = sqlite3_blob_read(_blob, buffer.Slice(0, count), (int)position);
             SqliteException.ThrowExceptionForRC(rc, _db);
             _position += count;
             return count;
@@ -198,11 +221,6 @@ public override int Read(byte[] buffer, int offset, int count)
         /// <param name="count">The number of bytes to be written to the current stream.</param>
         public override void Write(byte[] buffer, int offset, int count)
         {
-            if (!CanWrite)
-            {
-                throw new NotSupportedException(Resources.WriteNotSupported);
-            }
-
             if (buffer == null)
             {
                 throw new ArgumentNullException(nameof(buffer));
@@ -229,18 +247,40 @@ public override void Write(byte[] buffer, int offset, int count)
                 throw new ObjectDisposedException(objectName: null);
             }
 
+            Write(buffer.AsSpan(offset, count));
+        }
+
+        /// <summary>
+        ///     Writes a sequence of bytes to the current stream and advances the current position within this stream by
+        ///     the number of bytes written.
+        /// </summary>
+        /// <param name="buffer">
+        ///     A region of memory. This method copies the contents of this region to the current stream.
+        /// </param>
+#if NET
+        public override void Write(ReadOnlySpan<byte> buffer)
+#else
+        public virtual void Write(ReadOnlySpan<byte> buffer)
+#endif
+        {
+            if (!CanWrite)
+            {
+                throw new NotSupportedException(Resources.WriteNotSupported);
+            }
+
             var position = _position;
             if (position > Length)
             {
                 position = Length;
             }
 
+            var count = buffer.Length;
             if (position + count > Length)
             {
                 throw new NotSupportedException(Resources.ResizeNotSupported);
             }
 
-            var rc = sqlite3_blob_write(_blob, buffer.AsSpan(offset, count), (int)position);
+            var rc = sqlite3_blob_write(_blob, buffer.Slice(0, count), (int)position);
             SqliteException.ThrowExceptionForRC(rc, _db);
             _position += count;
         }