# HistogramBucket.msg

## Overview

`HistogramBucket.msg` describes a single bucket of a histogram. A bucket counts values `x` for which the following inequality holds:

```text
previous_boundary < x <= bucket_boundary
```

## Fields

| Field | Type | Description |
| --- | --- | --- |
| `bucket_boundary` | `float64` | The exclusive upper boundary of this bucket. |
| `count` | `float64` | The number of samples that fell into this bucket. |

## Usage

- Buckets are stored in ascending order of `bucket_boundary` in the `counts_by_bucket` array of `Metric.msg`.
- The first bucket's `previous_boundary` is negative infinity; the last bucket covers values greater than the largest explicit boundary.