Note for other people running into the error:
Number must be positive. (Parameter 'batchSize')
when executing AgentComponents agentComponents = new AgentComponents(elasticApmLogger, elasticApmConfig, null);
Solution
The reason is that MaxBatchEventCount in the IConfigurationReader implementation is 0. The documentation on the interface states:
The maximal number of events to send in a batch.
It's possible for a batch contain less then the maximum events
if there are events that need to be sent out because they were held for too long.
- Positive number - The maximal number of of events to send in a batch.
- 0 and negative - Invalid and the default value is used instead.
However, a value of zero will raise the error Number must be positive.
Using a negative value also raises Number must be positive.
Replace the value of the configuration option by a positive value like the default value 10 (see ConfigConsts.cs in the class DefaultValues).