Make throttle internal

# Motivation
During the discussion in apple#248 it became clear that the semantics of `throttle` are not 100% figured out yet.

# Modification
This PR is making `throttle` internal to remove it from the upcoming 1.0.0 release. This gives us more time to investigate what exact semantics we want to have.

Author: FranzBusch

Sources/AsyncAlgorithms/AsyncThrottleSequence.swift

@@ -12,19 +12,19 @@
 extension AsyncSequence {
   /// Create a rate-limited `AsyncSequence` by emitting values at most every specified interval.
   @available(macOS 13.0, iOS 16.0, watchOS 9.0, tvOS 16.0, *)
-  public func throttle<C: Clock, Reduced>(for interval: C.Instant.Duration, clock: C, reducing: @Sendable @escaping (Reduced?, Element) async -> Reduced) -> AsyncThrottleSequence<Self, C, Reduced> {
+  func throttle<C: Clock, Reduced>(for interval: C.Instant.Duration, clock: C, reducing: @Sendable @escaping (Reduced?, Element) async -> Reduced) -> AsyncThrottleSequence<Self, C, Reduced> {
     AsyncThrottleSequence(self, interval: interval, clock: clock, reducing: reducing)
   }
 
   /// Create a rate-limited `AsyncSequence` by emitting values at most every specified interval.
   @available(macOS 13.0, iOS 16.0, watchOS 9.0, tvOS 16.0, *)
-  public func throttle<Reduced>(for interval: Duration, reducing: @Sendable @escaping (Reduced?, Element) async -> Reduced) -> AsyncThrottleSequence<Self, ContinuousClock, Reduced> {
+  func throttle<Reduced>(for interval: Duration, reducing: @Sendable @escaping (Reduced?, Element) async -> Reduced) -> AsyncThrottleSequence<Self, ContinuousClock, Reduced> {
     throttle(for: interval, clock: .continuous, reducing: reducing)
   }
 
   /// Create a rate-limited `AsyncSequence` by emitting values at most every specified interval.
   @available(macOS 13.0, iOS 16.0, watchOS 9.0, tvOS 16.0, *)
-  public func throttle<C: Clock>(for interval: C.Instant.Duration, clock: C, latest: Bool = true) -> AsyncThrottleSequence<Self, C, Element> {
+  func throttle<C: Clock>(for interval: C.Instant.Duration, clock: C, latest: Bool = true) -> AsyncThrottleSequence<Self, C, Element> {
     throttle(for: interval, clock: clock) { previous, element in
       if latest {
         return element
@@ -36,14 +36,14 @@ extension AsyncSequence {
 
   /// Create a rate-limited `AsyncSequence` by emitting values at most every specified interval.
   @available(macOS 13.0, iOS 16.0, watchOS 9.0, tvOS 16.0, *)
-  public func throttle(for interval: Duration, latest: Bool = true) -> AsyncThrottleSequence<Self, ContinuousClock, Element> {
+  func throttle(for interval: Duration, latest: Bool = true) -> AsyncThrottleSequence<Self, ContinuousClock, Element> {
     throttle(for: interval, clock: .continuous, latest: latest)
   }
 }
 
 /// A rate-limited `AsyncSequence` by emitting values at most every specified interval.
 @available(macOS 13.0, iOS 16.0, watchOS 9.0, tvOS 16.0, *)
-public struct AsyncThrottleSequence<Base: AsyncSequence, C: Clock, Reduced> {
+struct AsyncThrottleSequence<Base: AsyncSequence, C: Clock, Reduced> {
   let base: Base
   let interval: C.Instant.Duration
   let clock: C
@@ -59,10 +59,10 @@ public struct AsyncThrottleSequence<Base: AsyncSequence, C: Clock, Reduced> {
 
 @available(macOS 13.0, iOS 16.0, watchOS 9.0, tvOS 16.0, *)
 extension AsyncThrottleSequence: AsyncSequence {
-  public typealias Element = Reduced
+  typealias Element = Reduced
 
   /// The iterator for an `AsyncThrottleSequence` instance.
-  public struct Iterator: AsyncIteratorProtocol {
+  struct Iterator: AsyncIteratorProtocol {
     var base: Base.AsyncIterator
     var last: C.Instant?
     let interval: C.Instant.Duration
@@ -76,7 +76,7 @@ extension AsyncThrottleSequence: AsyncSequence {
       self.reducing = reducing
     }
 
-    public mutating func next() async rethrows -> Reduced? {
+    mutating func next() async rethrows -> Reduced? {
       var reduced: Reduced?
       let start = last ?? clock.now
       repeat {
@@ -95,7 +95,7 @@ extension AsyncThrottleSequence: AsyncSequence {
     }
   }
 
-  public func makeAsyncIterator() -> Iterator {
+  func makeAsyncIterator() -> Iterator {
     Iterator(base.makeAsyncIterator(), interval: interval, clock: clock, reducing: reducing)
   }
 }