Add missing override for Write(ReadOnlySpan<byte> buffer)

Author: josesimoes

System.IO.FileSystem/FileStream.cs

@@ -545,6 +545,16 @@ public override void Write(byte[] buffer, int offset, int count)
             }
         }
 
+        /// <summary>
+        /// Writes a sequence of bytes from a read-only span to the current file stream and advances the current position within this file 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 file stream.</param>
+        /// <exception cref="IOException">The underlying pipe is closed or disconnected.</exception>
+        public override void Write(ReadOnlySpan<byte> buffer)
+        {
+            Write(buffer.ToArray(), 0, buffer.Length);
+        }
+
         /// <summary>
         /// Writes a byte to the current position in the file stream.
         /// </summary>