[C#][Unity] WebGL player build fails CS0305: IEnumerator ParseMessages requires 1 type argument #5759

Summary

Unity Editor Play Mode works. A WebGL Player build fails compiling sdks/csharp/src/SpacetimeDBClient.cs:

error CS0305: Using the generic type 'IEnumerator<T>' requires 1 type arguments

The WebGL-only coroutine path uses a non-generic IEnumerator, but the file imports System.Collections.Generic and does not import System.Collections.

Environment

• Unity 2022 (WebGL)
• com.clockworklabs.spacetimedbsdk v2.7.1 (88a4cad46c) — also reproduced by reading v2.8.1 / release/latest
• Same missing using on this repo’s v2.8.2 tag and current master (sdks/csharp/src/SpacetimeDBClient.cs)

Repro

1. Unity project with the C# client SDK (UPM git package).
2. Switch platform to WebGL and Build (not Enter Play Mode).
3. Compile error in SpacetimeDBClient.cs on:

#if UNITY_WEBGL && !UNITY_EDITOR
internal IEnumerator ParseMessages()

Play Mode does not hit this code (UNITY_EDITOR uses void ParseMessages() + Thread).

Cause

File header (v2.8.1 / master):

using System;
using System.Collections.Concurrent;
using System.Collections.Generic;

Non-generic IEnumerator lives in System.Collections. With only Generic imported, the compiler binds IEnumerator to IEnumerator<T> → CS0305.

An older WebGL-related revision of this file did include using System.Collections; (e.g. around the original WebGL coroutine work). It appears to have been dropped in later edits of SpacetimeDBClient.cs.

Suggested fix

Add to sdks/csharp/src/SpacetimeDBClient.cs:

using System.Collections;

(or fully qualify System.Collections.IEnumerator on the WebGL #if branch).

Please ship this in the next Unity UPM tag as well (com.clockworklabs.spacetimedbsdk); that package currently lags and still mirrors the broken header at v2.8.1.