Throttle Function Not Delaying Stream as Expected

describe("String to Stream", () => {  
  it("should split a string into words and emit each word every second", async () => {  
    const input = "This is an example string."  
    const words = input.split(" ")  
      
    const collected: string[] = []  
      
    const program = pipe(  
      Stream.fromIterable(words),  
      Stream.throttle({ cost: () => 1, units: 1, duration: Duration.seconds(1) }),  
      Stream.tap((word) => Effect.sync(() => {  
        collected.push(word)  
      })),
      Stream.runDrain  
    )  
      
    await Effect.runPromise(program)  
      
    expect(collected).toEqual(words)  
  })  
})