sshbuf_peek_u64
ASSERT_INT_EQ(sshbuf_peek_u64(p1, 0, &v64), 0);
ASSERT_INT_EQ(sshbuf_peek_u64(p1, 2, &v64), 0);
ASSERT_INT_EQ(sshbuf_peek_u64(p1, 3, &v64), SSH_ERR_MESSAGE_INCOMPLETE);
ASSERT_INT_EQ(sshbuf_peek_u64(p1, sizeof(x), &v64),
ASSERT_INT_EQ(sshbuf_peek_u64(p1, 1000, &v64),
int sshbuf_peek_u64(const struct sshbuf *buf, size_t offset,