prefetch: byRequest, whenFull: .dropOldest
import Combine
let input = PassthroughSubject<String, Never>()
let output = input.buffer(size: 3, prefetch: .byRequest, whenFull: .dropOldest)
.makeConnectable()
output.connect()
input.send("1")
input.send("2")
input.send("3")
input.send("4")
input.send("5")
output.sink { (value) in
print(value)
}
3
4
5