Fix spans for streaming responses in WSGI based frameworks #103

Job	Run time
Tasks (latest) (3.6, ubuntu-20.04)	1m 25s
Tasks (latest) (3.7, ubuntu-20.04)	2m 19s
Tasks (latest) (3.8, ubuntu-20.04)	3m 52s
Tasks (latest) (3.10, ubuntu-20.04)	2m 57s
Tasks (latest) (3.11, ubuntu-20.04)	3m 14s
Tasks (pinned) (3.6, ubuntu-20.04)	3m 29s
Tasks (pinned) (3.7, ubuntu-20.04)	4m 4s
Tasks (latest) (3.12, ubuntu-20.04)	4m 55s
Tasks (latest) (3.13, ubuntu-20.04)	4m 55s
Tasks (pinned) (3.8, ubuntu-20.04)	3m 46s
Tasks (pinned) (3.9, ubuntu-20.04)	2m 3s
Tasks (pinned) (3.10, ubuntu-20.04)	4m 8s
Tasks (pinned) (3.11, ubuntu-20.04)	4m 53s
Tasks (pinned) (3.12, ubuntu-20.04)	3m 47s
All pinned Tasks tests passed	1s
	49m 48s

Provide feedback