Fix #380, Support polling with no delay

Checklist (Please check before submitting)

[x] I reviewed the Contributing Guide.
[x] I signed and emailed the appropriate Contributor License Agreement to GSFC-SoftwareRelease@mail.nasa.gov and copied cfs-program@lists.nasa.gov.

Describe the contribution

Testing performed CI and custom distro with zero delay, confirmed faster than 1 second polling

Expected behavior changes Supports polling with zero timeout

System(s) tested on Ubuntu 20.04

Additional context Project request

Third party code None

Contributor Info - All information REQUIRED for consideration of pull request Jacob Hageman - NASA/GSFC

nasa / CF