SHAKE128_BLOCK_SIZE
.ctx.block_size = SHAKE128_BLOCK_SIZE,
u8 block[SHAKE128_BLOCK_SIZE + 1];
u8 block[SHAKE128_BLOCK_SIZE + 1])
shake_squeeze(shake, block, SHAKE128_BLOCK_SIZE);
block[SHAKE128_BLOCK_SIZE] = 0; /* for KMSAN */
static_assert(SHAKE128_BLOCK_SIZE % 3 == 0);
for (int j = 0; j < SHAKE128_BLOCK_SIZE && i < N; j += 3) {