text: Title: uvicorn adding its own server header to response
  Body: ### Discussed in https://github.com/encode/uvicorn/discussions/1435
  
  <div type='discussions-op-text'>
  
  <sup>Originally posted by **udit-pandey** April  1, 2022</sup>
  I have added few headers using [secure package](https://pypi.org/project/secure/) in my fastapi application. I wanted to overwrite the server header(having default value "uvicorn") to something else. All the added headers using secure package are replicated in the responses except the server header which is coming twice(once with value given by me and other with uvicorn) as shown the postman api response below:
  
  ![image](https://user-images.githubusercontent.com/18224381/161194376-1ff92c6c-ed3e-41c6-9578-39993ea17179.png)
  
  I run my application using:
  `gunicorn -k uvicorn.workers.UvicornWorker ${APP_MODULE} --bind 0.0.0.0:80`
  
  Why is this header being added again by **uvicorn** even though it already exists?</div>