add buffer operator to supported operators list
add buffer operator to supported operators list

petester42/RxSwift,thanegill/RxSwift,tottakai/RxSwift,hsoi/RxSwift,kousun12/RxSwift,kzaher/RxSwift,ReactiveX/RxSwift,KyoheiG3/RxSwift,tottakai/RxSwift,petester42/RxSwift,thanegill/RxSwift,KyoheiG3/RxSwift,shiratsu/RxSwift,Pluto-tv/RxSwift,Pluto-tv/RxSwift,ashfurrow/RxSwift,kousun12/RxSwift,kzaher/RxSwift,petester42/RxSwift,ReactiveX/RxSwift,petester42/RxSwift,cfraz89/RxSwift,thanegill/RxSwift,hsoi/RxSwift,cfraz89/RxSwift,Pluto-tv/RxSwift,cfraz89/RxSwift,hsoi/RxSwift,kousun12/RxSwift,hsoi/RxSwift,shiratsu/RxSwift,KyoheiG3/RxSwift,Pluto-tv/RxSwift,thanegill/RxSwift,kousun12/RxSwift,ashfurrow/RxSwift,ashfurrow/RxSwift,kzaher/RxSwift,ashfurrow/RxSwift,tottakai/RxSwift,kzaher/RxSwift,cfraz89/RxSwift,ReactiveX/RxSwift,shiratsu/RxSwift