This read-only PmBinState object reports the state of this specific history bin, per its description, presumably distinguishing states such as whether the bin has completed its full collection period, is still actively accumulating, or was only partially valid due to a mid-period event. This state field is what tells an engineer whether a given bin's counter values represent a complete, trustworthy measurement period or a partial/invalid one that shouldn't be used for rate calculations or SLA reporting. An engineer generating an SLA report from historical bins would filter out any bins whose state doesn't indicate a fully complete collection period, to avoid skewing the report with partial data.