Merge "Add a comment on thread-safety for NDK" into main

 * API, the client is expected to call {@link APerformanceHint_reportActualWorkDuration} each

 * cycle to report the actual time taken to complete to the system.

 *

 * Note, methods of {@link APerformanceHintSession_*} are not thread safe so callers must

 * ensure thread safety.

 *

 * All timings should be from `std::chrono::steady_clock` or `clock_gettime(CLOCK_MONOTONIC, ...)`

 */

typedef struct APerformanceHintSession APerformanceHintSession;