pub unsafe extern "C" fn otCoapMessageAppendObserveOption(
    aMessage: *mut otMessage,
    aObserve: u32
) -> otError
Expand description

Appends an Observe option.

@param[in,out] aMessage A pointer to the CoAP message. @param[in] aObserve Observe field value.

@retval OT_ERROR_NONE Successfully appended the option. @retval OT_ERROR_INVALID_ARGS The option type is not equal or greater than the last option type. @retval OT_ERROR_NO_BUFS The option length exceeds the buffer size.