FlatBufferBuilder builder = new FlatBufferBuilder(1024); string message = "Hello, world!"; int messageOffset = builder.CreateString(message);In this example, a FlatBufferBuilder instance is created with a buffer size of 1024. Then, a sample string "Hello, world!" is assigned to the message variable. The CreateString method is called on the builder object with the message string as a parameter, and the returned int value is stored in the messageOffset variable. This offset can be used to refer to the string within the serialized data. The package library of FlatBuffers for C# is FlatBuffers.CSharp.