add flatbuffers

commit 6da1cf79d90eb242e7da5318241d42279a3df3ba
Author: Max Burke <max@urbanlogiq.com>
Date:   Sun Jan 19 14:47:28 2020 -0800

    [rust] Add use declarations to Rust-generated bindings for imported FB definitions (#5645)

    * Bugfix for Rust generation of union fields named with language keywords

flatbuffers/net/FlatBuffers/ByteBufferUtil.cs

@@ -0,0 +1,39 @@
+/*
+ * Copyright 2017 Google Inc. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+using System;
+
+namespace FlatBuffers
+{
+	/// <summary>
+	/// Class that collects utility functions around `ByteBuffer`.
+	/// </summary>
+	public class ByteBufferUtil
+	{
+		// Extract the size prefix from a `ByteBuffer`.
+		public static int GetSizePrefix(ByteBuffer bb) {
+			return bb.GetInt(bb.Position);
+		}
+
+		// Create a duplicate of a size-prefixed `ByteBuffer` that has its position
+		// advanced just past the size prefix.
+		public static ByteBuffer RemoveSizePrefix(ByteBuffer bb) {
+			ByteBuffer s = bb.Duplicate();
+			s.Position += FlatBufferConstants.SizePrefixLength;
+			return s;
+		}
+	}
+}