fix: surface StreamTarget write errors instead of swallowing them (#305)

* fix: await StreamTarget writes to prevent overlapping OPFS operations

* no need for flush

* preserve fire and forget writes

* Remove pendingWrites, add missing mutex acquire to ADTS muxer finalize method

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Co-authored-by: Vanilagy <[email protected]>

src/adts/adts-muxer.ts

@@ -111,5 +111,8 @@ export class AdtsMuxer extends Muxer {
 		throw new Error('ADTS does not support subtitles.');
 	}
 
-	async finalize() {}
+	async finalize() {
+		const release = await this.mutex.acquire(); // Required so that finalize() can't resolve before other calls
+		release();
+	}
 }