Handle HTTP 206 responses from timelines endpoint

Packages/Pachyderm/Sources/Pachyderm/Client.swift

@@ -83,7 +83,7 @@ public class Client {
                     completion(.failure(Error(request: request, type: .invalidResponse)))
                     return
             }
-            guard response.statusCode == 200 else {
+            guard response.statusCode == 200 || request.additionalAcceptableHTTPCodes.contains(response.statusCode) else {
                 let mastodonError = try? Client.decoder.decode(MastodonError.self, from: data)
                 let type: ErrorType = mastodonError.flatMap { .mastodonError(response.statusCode, $0.description) } ?? .unexpectedStatus(response.statusCode)
                 completion(.failure(Error(request: request, type: type)))

Packages/Pachyderm/Sources/Pachyderm/Model/Timeline.swift

@@ -38,6 +38,8 @@ extension Timeline {
             request.queryParameters.append("local" => true)
         }
         request.range = range
+        // 206 can happen when the timeline is being regenerated and therefore is incomplete
+        request.additionalAcceptableHTTPCodes = [206]
         return request
     }
 }

Packages/Pachyderm/Sources/Pachyderm/Request/Request.swift

@@ -13,6 +13,7 @@ public struct Request<ResultType: Decodable>: Sendable {
     let endpoint: Endpoint
     let body: Body
     var queryParameters: [Parameter]
+    var additionalAcceptableHTTPCodes: [Int] = []
     
     init(method: Method, path: Endpoint, body: Body = EmptyBody(), queryParameters: [Parameter] = []) {
         self.method = method