TelemetryClient shares Backoff and its retry count across all batches sent #338
Description
#334 introduced a bug that causes all batches to share the same Backoff object, and thus share a single retry count. Obvious thread-safety issues aside, reusing the Backoff object means only Backoff#maxRetries retries for the lifetime of the process. This results in a large volume of errors like [EventBatch] - Max retries exceeded. Dropping <N> pieces of data!] and data being dropped.
A copy of the backoff policy should be made at https://github.com/newrelic/newrelic-telemetry-sdk-java/blob/main/telemetry-core/src/main/java/com/newrelic/telemetry/TelemetryClient.java#L200