Function unique_optimized 

pub fn unique_optimized<T>(
    a: &Array<T>,
    axis: Option<usize>,
    return_index: Option<bool>,
    return_inverse: Option<bool>,
    return_counts: Option<bool>,
) -> Result<UniqueResult<T>>
where
    T: Clone + Hash + Eq + Debug + Zero + Send + Sync,

Optimized version of the unique function to find unique elements of an array.

This version includes several optimizations over the standard unique function:

• Parallel processing for large arrays
• Pre-allocated buffers to reduce memory allocations
• Early capacity estimation based on input size
• SIMD-friendly memory access patterns where possible

Parameters

• a - Input array
• axis - Optional axis along which to find unique elements
• return_index - If true, also return the indices of the first occurrences
• return_inverse - If true, also return the indices to reconstruct the original array
• return_counts - If true, also return the counts of each unique value

Returns

A UniqueResult struct containing some or all of:

• The unique values in the array (required)
• The indices of the first unique values (if return_index is true)
• The indices to reconstruct the original array (if return_inverse is true)
• The counts of each unique value (if return_counts is true)