Don't drop items to write when sending fast

src/Speckle.Sdk.Dependencies/Serialization/ChannelSaver.cs

@@ -8,7 +8,7 @@ namespace Speckle.Sdk.Dependencies.Serialization;
 public abstract class ChannelSaver<T>
   where T : IHasByteSize
 {
-  private const int SEND_CAPACITY = 500;
+  private const int SEND_CAPACITY = 5000;
   private const int HTTP_SEND_CHUNK_SIZE = 25_000_000; //bytes
   private static readonly TimeSpan HTTP_BATCH_TIMEOUT = TimeSpan.FromSeconds(2);
   private const int MAX_PARALLELISM_HTTP = 4;
@@ -68,14 +68,13 @@ public abstract class ChannelSaver<T>
         TaskScheduler.Current
       );
 
-  public void Save(T item)
+  public async Task SaveAsync(T item, CancellationToken cancellationToken)
   {
     if (Exception is not null)
     {
       return; //don't save if we're already done through an error
     }
-    // ReSharper disable once MethodSupportsCancellation
-    _checkCacheChannel.Writer.TryWrite(item);
+    await _checkCacheChannel.Writer.WriteAsync(item, cancellationToken).ConfigureAwait(false);
   }
 
   private async Task<IMemoryOwner<T>> SendToServer(IMemoryOwner<T> batch)

src/Speckle.Sdk/Serialisation/V2/Send/ObjectSaver.cs

@@ -12,7 +12,7 @@ public interface IObjectSaver : IDisposable
   Task Start(int? maxParallelism, int? httpBatchSize, int? cacheBatchSize, CancellationToken cancellationToken);
   void DoneTraversing();
   Task DoneSaving();
-  void SaveItem(BaseItem item);
+  Task SaveAsync(BaseItem item);
   long Uploaded { get; }
   long Cached { get; }
 }
@@ -81,10 +81,10 @@ public sealed class ObjectSaver(
     }
   }
 
-  public void SaveItem(BaseItem item)
+  public async Task SaveAsync(BaseItem item)
   {
     Interlocked.Increment(ref _objectsSerialized);
-    Save(item);
+     await SaveAsync(item, _cancellationTokenSource.Token).ConfigureAwait(false);
   }
 
   public override void SaveToCache(List<BaseItem> batch)

src/Speckle.Sdk/Serialisation/V2/Send/SerializeProcess.cs

@@ -258,7 +258,7 @@ public sealed class SerializeProcess(
             }
 
             Interlocked.Increment(ref _objectsSerialized);
-            objectSaver.SaveItem(item);
+            await objectSaver.SaveAsync(item).ConfigureAwait(false);
           }
 
           if (!currentClosures.ContainsKey(item.Id))