create_attachment in wiki_client unable to upload png files

I am trying to create a png file as attachment in azure wiki as code and getting the following issue:

azure.devops.exceptions.AzureDevOpsServiceError: The wiki attachment creation failed with message : The input is not a valid Base-64 string as it contains a non-base 64 character, more than two padding characters, or an illegal character among the padding characters.

This is the snippet

version_descriptor = GitVersionDescriptor(version="main",version_type="branch")
with open("./sample-image.png","rb") as png_file:
    wiki_client.create_attachment(upload_stream=png_file, version_descriptor=version_descriptor, project="<project-name>", wiki_identifier="<wiki-name>",  name="sample-image.png")

从 wiki_client.create_attachment 开始，使用提供的二进制 PNG 上传代码片段复现该失败。跟踪在 Azure Wiki 请求之前如何处理 upload_stream；当 PNG 附件能够成功创建且不再出现 Base-64 错误时，即视为完成。