unix/moduselect: Implement ipoll() method with no-allocation policy.
unix/moduselect: Implement ipoll() method with no-allocation policy.

ipoll() allows to poll streams without allocating any memory: this method
returns an iterator (a poll object itself), and the iterator yields
preallocated "callee-owned tuple" with polling results for each active
stream. The only operation a caller is allowed to do with this tuple is
extracting values from it (storing the tuple as a whole somewhere is
not allowed).

kerneltask/micropython,selste/micropython,MrSurly/micropython-esp32,cwyark/micropython,adafruit/micropython,pfalcon/micropython,adafruit/circuitpython,trezor/micropython,hiway/micropython,torwag/micropython,dmazzella/micropython,selste/micropython,MrSurly/micropython,cwyark/micropython,oopy/micropython,ryannathans/micropython,tralamazza/micropython,lowRISC/micropython,swegener/micropython,pramasoul/micropython,micropython/micropython-esp32,dmazzella/micropython,Peetz0r/micropython-esp32,infinnovation/micropython,oopy/micropython,henriknelson/micropython,PappaPeppar/micropython,bvernoux/micropython,infinnovation/micropython,pfalcon/micropython,AriZuu/micropython,micropython/micropython-esp32,MrSurly/micropython,PappaPeppar/micropython,HenrikSolver/micropython,lowRISC/micropython,puuu/micropython,oopy/micropython,MrSurly/micropython-esp32,oopy/micropython,infinnovation/micropython,Peetz0r/micropython-esp32,AriZuu/micropython,swegener/micropython,TDAbboud/micropython,TDAbboud/micropython,ryannathans/micropython,torwag/micropython,HenrikSolver/micropython,tobbad/micropython,pramasoul/micropython,pozetroninc/micropython,tralamazza/micropython,toolmacher/micropython,adafruit/circuitpython,tralamazza/micropython,blazewicz/micropython,cwyark/micropython,pfalcon/micropython,selste/micropython,AriZuu/micropython,lowRISC/micropython,kerneltask/micropython,alex-robbins/micropython,micropython/micropython-esp32,torwag/micropython,kerneltask/micropython,pramasoul/micropython,oopy/micropython,bvernoux/micropython,dmazzella/micropython,AriZuu/micropython,deshipu/micropython,henriknelson/micropython,tobbad/micropython,trezor/micropython,adafruit/circuitpython,cwyark/micropython,MrSurly/micropython-esp32,infinnovation/micropython,chrisdearman/micropython,adafruit/circuitpython,Peetz0r/micropython-esp32,lowRISC/micropython,deshipu/micropython,chrisdearman/micropython,tobbad/micropython,toolmacher/micropython,micropython/micropython-esp32,Timmenem/micropython,pozetroninc/micropython,tobbad/micropython,TDAbboud/micropython,kerneltask/micropython,cwyark/micropython,blazewicz/micropython,chrisdearman/micropython,bvernoux/micropython,henriknelson/micropython,hiway/micropython,TDAbboud/micropython,Timmenem/micropython,Peetz0r/micropython-esp32,SHA2017-badge/micropython-esp32,AriZuu/micropython,PappaPeppar/micropython,PappaPeppar/micropython,hiway/micropython,lowRISC/micropython,ryannathans/micropython,ryannathans/micropython,swegener/micropython,trezor/micropython,alex-robbins/micropython,Timmenem/micropython,chrisdearman/micropython,puuu/micropython,chrisdearman/micropython,trezor/micropython,alex-robbins/micropython,bvernoux/micropython,alex-robbins/micropython,swegener/micropython,Peetz0r/micropython-esp32,pfalcon/micropython,henriknelson/micropython,dmazzella/micropython,micropython/micropython-esp32,pfalcon/micropython,kerneltask/micropython,SHA2017-badge/micropython-esp32,blazewicz/micropython,adafruit/micropython,toolmacher/micropython,swegener/micropython,torwag/micropython,trezor/micropython,toolmacher/micropython,hiway/micropython,bvernoux/micropython,selste/micropython,ryannathans/micropython,adafruit/circuitpython,PappaPeppar/micropython,puuu/micropython,MrSurly/micropython,alex-robbins/micropython,TDAbboud/micropython,tralamazza/micropython,deshipu/micropython,pramasoul/micropython,SHA2017-badge/micropython-esp32,adafruit/circuitpython,blazewicz/micropython,pozetroninc/micropython,toolmacher/micropython,Timmenem/micropython,blazewicz/micropython,SHA2017-badge/micropython-esp32,hiway/micropython,MrSurly/micropython-esp32,MrSurly/micropython,torwag/micropython,MrSurly/micropython,adafruit/micropython,Timmenem/micropython,infinnovation/micropython,pozetroninc/micropython,puuu/micropython,adafruit/micropython,deshipu/micropython,pozetroninc/micropython,tobbad/micropython,selste/micropython,HenrikSolver/micropython,SHA2017-badge/micropython-esp32,MrSurly/micropython-esp32,HenrikSolver/micropython,henriknelson/micropython,deshipu/micropython,adafruit/micropython,puuu/micropython,HenrikSolver/micropython,pramasoul/micropython