Details

Changed Buckets from HashSet to ConcurrentDictionary (currently this can and will throw ocasionally)
Removed the RequestSemaphore that serialized all requests
To preserve the preemptive ratelimiting the following changes were made:
- Decrement the remaining number of requests before the reqest is made, to allow this to happen atomically the Remaining property was changed to have a explicit backing field
- Responses only update their ratelimit bucket when the response is for a newer interval than what the bucket currently points at. Otherwise this would push that remaining number of requests in that bucket back up when a response is received while other requests for that bucket are still pending
- A ManualResetEvent has been added to signal that the global ratelimit has been hit and further requests should be delayed temporarily
A HttpClientFactory has been added to allow for custom HttpClient implementation similar to how custom WebSocketClients and UdpClients are realized.

Notes

This should propably use a async implementation of the ManualResetEvent, but that would require additional dependencies and is only relevant in the case that the global ratelimit has been hit so I just used the framework implementation
- the one big issue this could cause is that when spamming requests a deadlock could occour where all Threads from the TaskPool are blocked by the Wait, so that there are none left to set the event. A similar issue can occour now when a Exception is thrown while performing the request so that the Semaphore is never released
This change will propably expose a couple of issues similar to #219 (closed) where the library assumes to be single-threaded while Tasks are in fact multi-threaded