docs: public static <T> int writeTo(LinkedBuffer buffer, T message, Schema<T> schema)
      {
          if (buffer.start != buffer.offset)
              throw new IllegalArgumentException("Buffer previously used and had not been reset.");
  
          final ProtobufOutput output = new ProtobufOutput(buffer);
          try
          {
              schema.writeTo(output, message);
          }
          catch (IOException e)
          {
              throw new RuntimeException("Serializing to a LinkedBuffer threw an IOException " +
                      "(should never happen).", e);
          }
  
          return output.getSize();
      }