Below, which statement is correct about the performance issue of a thread yielding itself when the intended lock is unavailable?$$

$1.$ "Yield" generates a context switch, which can worsen when more threads contend for shared resources.

$2.$ "Yield" leads to CPU time cycle waste because the thread does nothing but wait in the CPU.

$1$

$2$

$1$ and $2$

neither $1$ nor $2$