[Metrics SDK] Add support for Exponential Histogram Aggregation #1391
Description
Currently, metrics SDK implementation support following aggregation:
opentelemetry-cpp/sdk/include/opentelemetry/sdk/metrics/instruments.h
Lines 30 to 37 in 88e23ad
The default Histogram aggregation is implemented as described in the data model: https://github.com/open-telemetry/opentelemetry-specification/blob/90e5022a846a65600b7ad7e8d262678a83f76191/specification/metrics/datamodel.md#histogram
The data model also adds (experimental) support for Exponential histogram aggregation - https://github.com/open-telemetry/opentelemetry-specification/blob/90e5022a846a65600b7ad7e8d262678a83f76191/specification/metrics/datamodel.md#exponentialhistogram
This support needs to be implemented in the SDK.