struct DriverHeader { sim::Int32 stampHigh{ 0 }; sim::Int32 stampLow{ 0 }; sim::String frameId; };

The `struct` you've mentioned appears to be from a specific context that combines C++ and a simulation library (`sim`). Here's the explanation:

`DriverHeader` is a custom structure defined in your codebase, likely part of a simulation or robotics project using the `sim` library. It consists of three fields:
1. `stampHigh`: An integer (of type `sim::Int32`) representing the higher part of a timestamp.
2. `stampLow`: Another integer (also `sim::Int32`) representing the lower part of the timestamp.
3. `frameId`: A string variable storing the identifier for the current frame.

To work with this struct, you would typically create instances of it and manipulate its members like so:

// Create an instance of DriverHeader
DriverHeader header;

// Set the fields
header.stampHigh = 123456789;
header.stampLow = 987654321;
header.frameId = "Frame_01";

// Access or modify individual fields
std::cout << "Frame ID: " << header.frameId << std::endl;

However, since you also mentioned Spark ML and CSV data types issues, it seems unrelated to working directly with this C++ struct. If you need to handle similar data structures in a Spark ML pipeline, you might need to convert them into a format compatible with CSV or DenseVector before saving or processing.