[Dart] Implement putBool to fix errors when serializing structs with bools (#7359)

* [Dart] Implement putBool to fix errors when serializing structs with bools

* Add tests

dart/lib/flat_buffers.dart

@@ -401,6 +401,15 @@ class Builder {
     _setFloat32AtTail(_tail, value);
   }
 
+  /// Writes a bool to the tail of the buffer after preparing space for it.
+  /// Bools are represented as a Uint8, with the value set to '1' for true, and '0' for false
+  ///
+  /// Updates the [offset] pointer.  This method is intended for use when writing structs to the buffer.
+  void putBool(bool value) {
+    _prepare(_sizeofUint8, 1);
+    _buf.setInt8(_buf.lengthInBytes - _tail, value ? 1 : 0);
+  }
+
   /// Writes a Int64 to the tail of the buffer after preparing space for it.
   ///
   /// Updates the [offset] pointer.  This method is intended for use when writing structs to the buffer.

dart/test/bool_structs.fbs

@@ -0,0 +1,10 @@
+// Test for #7355
+table Foo {
+  my_foo : foo_properties;
+}
+
+struct foo_properties
+{
+    a : bool;
+    b : bool;
+}

dart/test/flat_buffers_test.dart

@@ -14,6 +14,7 @@ import 'package:test_reflective_loader/test_reflective_loader.dart';
 import './monster_test_my_game.example_generated.dart' as example;
 import './monster_test_my_game.example2_generated.dart' as example2;
 import './list_of_enums_generated.dart' as example3;
+import './bool_structs_generated.dart' as example4;
 import './keyword_test_keyword_test_generated.dart' as keyword_test;
 
 main() {
@@ -910,8 +911,11 @@ class GeneratorTest {
 @reflectiveTest
 class ListOfEnumsTest {
   void test_listOfEnums() async {
-    var mytable = example3.MyTableObjectBuilder(
-      options: [example3.OptionsEnum.A, example3.OptionsEnum.B, example3.OptionsEnum.C]);
+    var mytable = example3.MyTableObjectBuilder(options: [
+      example3.OptionsEnum.A,
+      example3.OptionsEnum.B,
+      example3.OptionsEnum.C
+    ]);
     var bytes = mytable.toBytes();
     var mytable_read = example3.MyTable(bytes);
     expect(mytable_read.options![0].value, example3.OptionsEnum.A.value);
@@ -919,3 +923,15 @@ class ListOfEnumsTest {
     expect(mytable_read.options![2].value, example3.OptionsEnum.C.value);
   }
 }
+
+@reflectiveTest
+class BoolInStructTest {
+  void test_boolInStruct() async {
+    var mystruct = example4.FooObjectBuilder(
+        myFoo: example4.FooPropertiesObjectBuilder(a: true, b: false));
+    var bytes = mystruct.toBytes();
+    var mystruct_read = example4.Foo(bytes);
+    expect(mystruct_read.myFoo!.a, true);
+    expect(mystruct_read.myFoo!.b, false);
+  }
+}