eventlet.wsgi 中的 start_response定义

def start_response(status, response_headers, exc_info=None):
status_code[0] = status.split()[0]
if exc_info:
try:
if headers_sent:
# Re-raise original exception if headers sent
raise exc_info[0], exc_info[1], exc_info[2]
finally:
# Avoid dangling circular ref
exc_info = None

capitalized_headers = [('-'.join([x.capitalize()
for x in key.split('-')]), value)
for key, value in response_headers]

headers_set[:] = [status, capitalized_headers]
return write

capitalized_headers，
换言之，在整个应用的header都会被格式化成Content-Type这种首字母大写的格式。