codegen: Fix warning about copying delegate parameters in async method
codegen: Fix warning about copying delegate parameters in async method

rvu95/vala,tjol/vala-tjol,frida/vala,frida/vala,Distrotech/vala,spidermonkdust/vala,kamanashisroy/aroop,jessevdk/vala,jessevdk/vala,flobrosch/vala-fixes,jessevdk/vala,severinh/vala,rvu95/vala,frida/vala,GNOME/vala,Distrotech/vala,playya/vala,spidermonkdust/vala,flobrosch/vala-fixes,frida/vala,xdave/pvala,kamanashisroy/aroop,GNOME/vala,rvu95/vala,severinh/vala,playya/vala,spidermonkdust/vala,tjol/vala-tjol,kamanashisroy/aroop,tjol/vala-tjol,GNOME/vala,severinh/vala,GNOME/vala,Distrotech/vala,frida/vala,playya/vala,flobrosch/vala-fixes