Corrected typo in docstring. s/backpressue/backpressure.
Corrected typo in docstring. s/backpressue/backpressure.

vrtsystems/pika,zixiliuyue/pika,shinji-s/pika,vitaly-krugl/pika,renshawbay/pika-python3,Zephor5/pika,jstnlef/pika,fkarb/pika-python3,reddec/pika,Tarsbot/pika,skftn/pika,benjamin9999/pika,knowsis/pika,pika/pika,hugoxia/pika