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/swift/Sources/FlatBuffers/Offset.swift

@@ -0,0 +1,12 @@
+import Foundation
+
+/// Offset object for all the Objects that are written into the buffer
+public struct Offset<T> {
+    /// Offset of the object in the buffer
+    public var o: UOffset
+    /// Returns false if the offset is equal to zero
+    public var isEmpty: Bool { return o == 0 }
+    
+    public init(offset: UOffset) { o = offset }
+    public init() { o = 0 }
+}