Function vsetq_lane_p8 

pub fn vsetq_lane_p8(a: u8, b: poly8x16_t, const LANE: i32) -> poly8x16_t

Available on little-endian and target feature neon and (AArch64 or ARM or ARM64EC) and (AArch64 or ARM64EC) and (AArch64 or ARM64EC or target feature v7) only.

Insert vector element from another vector element Arm’s documentation