LongGaugeBuilder (OpenTelemetry API)

```
public interface LongGaugeBuilder
```
A builder for Gauge metric types. These can only be asynchronously collected.

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`void`	`buildWithCallback(Consumer<ObservableLongMeasurement> callback)`	Builds this asynchronous insturment with the given callback.
`DoubleGaugeBuilder`	`ofDoubles()`	Sets the gauge for recording `double` values.
`LongGaugeBuilder`	`setDescription(String description)`	Sets the description for this instrument.
`LongGaugeBuilder`	`setUnit(String unit)`	Sets the unit of measure for this instrument.

- Method Detail
  - setDescription
```
LongGaugeBuilder setDescription(String description)
```
    Sets the description for this instrument.
    Description strings should follow the instrument description rules: https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/metrics/api.md#instrument-description
  - setUnit
```
LongGaugeBuilder setUnit(String unit)
```
    Sets the unit of measure for this instrument.
    Unit strings should follow the instrument unit rules: https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/metrics/api.md#instrument-unit
  - ofDoubles
```
DoubleGaugeBuilder ofDoubles()
```
    Sets the gauge for recording double values.
  - buildWithCallback
```
void buildWithCallback(Consumer<ObservableLongMeasurement> callback)
```
    Builds this asynchronous insturment with the given callback.
    The callback will only be called when the Meter is being observed.
    
    Parameters:
    
    callback - A state-capturing callback used to observe values on-demand.