Function duckdb_vector_copy_sel 

pub unsafe extern "C" fn duckdb_vector_copy_sel(
    src: duckdb_vector,
    dst: duckdb_vector,
    sel: duckdb_selection_vector,
    src_count: idx_t,
    src_offset: idx_t,
    dst_offset: idx_t,
)

Copy the src vector to the dst with a selection vector that identifies which indices to copy.

@param src The vector to copy from. @param dst The vector to copy to. @param sel The selection vector. The length of the selection vector should not be more than the length of the src vector @param src_count The number of entries from selection vector to copy. Think of this as the effective length of the selection vector starting from index 0 @param src_offset The offset in the selection vector to copy from (important: actual number of items copied = src_count - src_offset). @param dst_offset The offset in the dst vector to start copying to.