Write single file option enabled. Minor issues:

1. What if write_master_file = false
2. Finalized file statistics use wrong name

writer/HDF5DataFile.cpp

@@ -77,7 +77,7 @@ std::optional<HDF5DataFileStatistics> HDF5DataFile::Close() {
     }
     data_file.reset();
 
-    if (!std::filesystem::exists(filename.c_str()) || overwrite)
+    if (manage_file && (!std::filesystem::exists(filename.c_str()) || overwrite))
         std::rename(tmp_filename.c_str(), filename.c_str());
 
     closed = true;
@@ -102,7 +102,7 @@ HDF5DataFile::~HDF5DataFile() {
     }
 }
 
-void HDF5DataFile::CreateFile(const DataMessage& msg) {
+void HDF5DataFile::CreateFile(const DataMessage& msg, std::shared_ptr<HDF5File> in_data_file) {
     HDF5Dcpl dcpl;
 
     HDF5DataType data_type(msg.image.GetMode());
@@ -130,7 +130,7 @@ void HDF5DataFile::CreateFile(const DataMessage& msg) {
             break;
     }
 
-    data_file = std::make_unique<HDF5File>(tmp_filename);
+    data_file = in_data_file;
 
     HDF5Group(*data_file, "/entry").NXClass("NXentry");
     HDF5Group(*data_file, "/entry/data").NXClass("NXdata");
@@ -149,11 +149,10 @@ void HDF5DataFile::Write(const DataMessage &msg, uint64_t image_number) {
     if (image_number >= images_per_file)
         throw JFJochException(JFJochExceptionCategory::FileWriteError,
             "Image number out of bounds");
-    bool new_file = false;
 
     if (!data_file) {
-        CreateFile(msg);
-        new_file = true;
+        manage_file = true;
+        CreateFile(msg, std::make_shared<HDF5File>(tmp_filename));
     }
 
     if (new_file || (static_cast<int64_t>(image_number) > max_image_number)) {
@@ -161,6 +160,7 @@ void HDF5DataFile::Write(const DataMessage &msg, uint64_t image_number) {
         timestamp.resize(max_image_number + 1);
         exptime.resize(max_image_number + 1);
         number.resize(max_image_number + 1);
+        new_file = false;
     }
 
     nimages++;