# Structs
Bin: A bin is a discrete portion of data spanning from start to end, or if no end is given, then from start to +inf.
CollectionPeriod: The collection period is a date range which includes the `first` and `last` day.
Date: Represents a whole or partial calendar date, such as a birthday.
FractionTimeseries: For enum metrics, provides fraction timeseries which add up to approximately 1.0 per entry (k-th element into the repeated fractions field for any k <= len) across fraction_timeseries.
HistoryKey: Key defines all the dimensions that identify this record as unique.
HistoryRecord: HistoryRecord is a timeseries of Chrome UX Report data.
Key: Key defines all the dimensions that identify this record as unique.
Metric: A `metric` is a set of user experience data for a single web performance metric, like "first contentful paint".
MetricTimeseries: A `metric timeseries` is a set of user experience data for a single web performance metric, like "first contentful paint".
Percentiles: Percentiles contains synthetic values of a metric at a given statistical percentile.
QueryHistoryRequest: Request payload sent by a physical web client.
QueryHistoryResponse: Response payload sent back to a physical web client.
QueryRequest: Request payload sent by a physical web client.
QueryResponse: Response payload sent back to a physical web client.
Record: Record is a single Chrome UX report data record.
TimeseriesBin: A bin is a discrete portion of data spanning from start to end, or if no end is given, then from start to +inf.
TimeseriesPercentiles: Percentiles contains synthetic values of a metric at a given statistical percentile.
UrlNormalization: Object representing the normalization actions taken to normalize a url to achieve a higher chance of successful lookup.