From a68c76979d646fa90a24bff3457be2da0c371f0a Mon Sep 17 00:00:00 2001
From: Jacob Bandes-Storch <jacob@foxglove.dev>
Date: Wed, 30 Aug 2023 11:00:11 -0700
Subject: [PATCH] swift: flush writer buffer when closing a chunk (#960)

### Public-Facing Changes

Swift: data is now properly sent to the writer each time a chunk is
closed.

### Description
---
 swift/mcap/MCAPWriter.swift | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/swift/mcap/MCAPWriter.swift b/swift/mcap/MCAPWriter.swift
index 8232b0203b..d120c67053 100644
--- a/swift/mcap/MCAPWriter.swift
+++ b/swift/mcap/MCAPWriter.swift
@@ -161,6 +161,9 @@ public final class MCAPWriter {
       }
     } else {
       message.serialize(to: &buffer)
+      if buffer.count >= options.chunkSize {
+        await _flush()
+      }
     }
   }
 
@@ -219,6 +222,7 @@ public final class MCAPWriter {
 
     let chunkStartOffset = _position()
     chunk.serialize(to: &buffer)
+    await _flush()
     let messageIndexStartOffset = _position()
 
     var messageIndexOffsets: [ChannelID: UInt64] = [:]