Why is this a technically difficult task? Why not just a function of 100 lines?

A task can be technically complex not because of the amount of code, but due to requirements for reliability, scalability, error handling, and architectural features.

Simply writing a function of 100 lines is not always a solution. The complexity may lie in:

• Ensuring concurrent access and data synchronization.
• Handling multiple exceptional situations and errors.
• Integrating with external systems with unstable behavior.
• Optimizing performance and resource usage.
• Supporting extensibility and modularity of the code.

For example, in Go, it is often necessary to consider goroutines, channels, and contexts for proper management of parallelism and cancellation of operations, which requires careful design rather than just writing a long function.