Fix warning on platforms where `time_t` is 32-bits
Fix warning on platforms where `time_t` is 32-bits

Explicitly downcast nanoseconds from `uint64_t` to `time_t` to handle
cases where `time_t` is only 32-bits long.

Closes #11.

commit 0a0f3f77ba92b014e2870d9add4813ada6ad1474
Author: Matthew Yu <matyu@microsoft.com>
Date:   Thu Feb 18 12:12:42 2021 -0800

    Change cast from long to time_t

commit 0967e294dcdbb2c7bcbf2aff97bd5ec68be9394b
Author: Matthew Yu <matyu@microsoft.com>
Date:   Thu Feb 18 11:43:32 2021 -0800

    Initial commit

neosmart/pevents,neosmart/pevents