Function otPlatRadioSleep 

pub unsafe extern "C" fn otPlatRadioSleep(
    aInstance: *mut otInstance,
) -> otError

Transition the radio to the Sleep state (turn off the radio).

If the radio is already in the Sleep state, this function MUST return OT_ERROR_NONE with no effect.

If otPlatRadioSleep() is called while the radio is in the middle of receiving a frame or transmitting an ACK (e.g., during AIFS/turnaround wait or actively transmitting the ACK frame), the radio MUST complete the ongoing operation (finish frame reception and/or ACK transmission) and transition to Sleep immediately thereafter. In this scenario:

• The radio MUST return OT_ERROR_NONE to indicate that the sleep request has been accepted and scheduled.
• Upon finishing the frame reception (and any associated ACK transmission), the radio driver MUST invoke otPlatRadioReceiveDone() to deliver the received frame (or report reception error) before transitioning to Sleep.

If any subsequent radio state transition function (e.g., otPlatRadioReceive() or otPlatRadioTransmit()) is called while a scheduled transition to Sleep is pending, the pending Sleep transition MUST be canceled/superseded, and the radio MUST transition to the newly requested state upon completing the ongoing reception and/or ACK transmission.

@param[in] aInstance The OpenThread instance structure.

@retval OT_ERROR_NONE Successfully transitioned to Sleep, radio is already in Sleep, or transition is accepted and scheduled. @retval OT_ERROR_BUSY The radio was transmitting a frame (initiated by otPlatRadioTransmit()). @retval OT_ERROR_INVALID_STATE The radio was disabled.