code: BufferAllocator allocator() {
      Class<?> allocator = reader.getClass(ALLOCATOR, UnpooledUnsafeHeapAllocator.class);
      try {
        return (BufferAllocator) allocator.newInstance();
      } catch (InstantiationException | IllegalAccessException e) {
        throw new ConfigurationException(e);
      } catch (ClassCastException e) {
        throw new ConfigurationException("invalid allocator class: " + allocator.getName());
      }
    }
docs: Returns the serializer buffer allocator.
  
  @return The serializer buffer allocator.