append_log_content returns HTTP 400 (Content-Length not set)

When using append_log_content, it returns HTTP 400 status code, and '{"count":55,"value":"ContentLength header must be specified to create a log."}'

DevOps: Azure DevOps Server 2020 update 1.1
azure-devops-python-api: 6.0.0b4

I workaround it with an explicit Content-Length header:

def append_log_content(self, content, scope_identifier, hub_name, plan_id, log_id):
        """AppendLogContent.
        :param bytes content: The content to be append
        :param str scope_identifier: The project GUID to scope the request
        :param str hub_name: The name of the server hub: "build" for the Build server or "rm" for the Release Management server
        :param str plan_id:
        :param int log_id:
        :rtype: :class:`<TaskLog> <azure.devops.v5_1.task.models.TaskLog>`
        """
        route_values = {}
        if scope_identifier is not None:
            route_values['scopeIdentifier'] = self._serialize.url('scope_identifier', scope_identifier, 'str')
        if hub_name is not None:
            route_values['hubName'] = self._serialize.url('hub_name', hub_name, 'str')
        if plan_id is not None:
            route_values['planId'] = self._serialize.url('plan_id', plan_id, 'str')
        if log_id is not None:
            route_values['logId'] = self._serialize.url('log_id', log_id, 'int')
        response = self._send(http_method='POST',
                              location_id='46f5667d-263a-4684-91b1-dff7fdcf64e2',
                              version='5.1',
                              route_values=route_values,
                              content=content,
                              media_type='application/octet-stream',
                              additional_headers={"Content-Length": len(content)})
        return self._deserialize('TaskLog', response)

从 issue 中所示的 append_log_content 入口点开始，检查其 _send 调用如何为 application/octet-stream 内容构造标头。重现 Azure DevOps Server 2020 请求，然后验证该请求包含 Content-Length 且不再返回 HTTP 400。