Rust structz (#6539)

* Rust structz

* struct of structs test

* swift tmp variables

Co-authored-by: Casper Neo <cneo@google.com>

tests/MyGame/Example/StructOfStructs.lua

@@ -0,0 +1,45 @@
+-- automatically generated by the FlatBuffers compiler, do not modify
+
+-- namespace: Example
+
+local flatbuffers = require('flatbuffers')
+
+local StructOfStructs = {} -- the module
+local StructOfStructs_mt = {} -- the class metatable
+
+function StructOfStructs.New()
+    local o = {}
+    setmetatable(o, {__index = StructOfStructs_mt})
+    return o
+end
+function StructOfStructs_mt:Init(buf, pos)
+    self.view = flatbuffers.view.New(buf, pos)
+end
+function StructOfStructs_mt:A(obj)
+    obj:Init(self.view.bytes, self.view.pos + 0)
+    return obj
+end
+function StructOfStructs_mt:B(obj)
+    obj:Init(self.view.bytes, self.view.pos + 8)
+    return obj
+end
+function StructOfStructs_mt:C(obj)
+    obj:Init(self.view.bytes, self.view.pos + 12)
+    return obj
+end
+function StructOfStructs.CreateStructOfStructs(builder, a_id, a_distance, b_a, b_b, c_id, c_distance)
+    builder:Prep(4, 20)
+    builder:Prep(4, 8)
+    builder:PrependUint32(c_distance)
+    builder:PrependUint32(c_id)
+    builder:Prep(2, 4)
+    builder:Pad(1)
+    builder:PrependInt8(b_b)
+    builder:PrependInt16(b_a)
+    builder:Prep(4, 8)
+    builder:PrependUint32(a_distance)
+    builder:PrependUint32(a_id)
+    return builder:Offset()
+end
+
+return StructOfStructs -- return the module