Fix delimited proto reader silently dropping messages that exceed the…

… default bufio.Scanner buffer max size

protoutils/delimited_protos.go

@@ -130,8 +130,15 @@ func (o *DelimitedProtoReader[T, M]) allWithMessageProvider(getMessage func() M)
 // yielded may be overwritten on subsequent iterations. If you need to use the
 // yieded []byte outside an iteration you must copy it somewhere else.
 func (o *RawDelimitedProtoReader) All() iter.Seq[[]byte] {
+	// 2 GiB, as defined by the protobuf spec
+	const protoMaxBytes = 1024 * 1024 * 1024 * 2
+	// Max message size + 4 bytes for the length header
+	const bufferMaxSize = protoMaxBytes + 4
 	return func(yield func([]byte) bool) {
 		scanner := bufio.NewScanner(o.reader)
+		// Start with no buffer and let bufio figure out the initial allocation +
+		// when it needs to be resized.
+		scanner.Buffer(nil, bufferMaxSize)
 		scanner.Split(splitMessages)
 
 		for scanner.Scan() {