Document batchSize config for OTLP registry

Resolves gh-5578

Author: shakuzen

docs/modules/ROOT/pages/implementations/otlp.adoc

@@ -31,6 +31,7 @@ management:
       export:
         # Supported configs
         url: "https://otlp.example.com:4318/v1/metrics"
+        batchSize: 15000
         aggregationTemporality: "cumulative"
         headers:
           header1: value1
@@ -39,9 +40,10 @@ management:
 ----
 
 1. `url` - The URL to which data is reported. Defaults to `http://localhost:4318/v1/metrics`
-2. `aggregationTemporality` - https://opentelemetry.io/docs/specs/otel/metrics/data-model/#temporality[Aggregation temporality, window=_blank] determines how the additive quantities are expressed, in relation to time. The supported values are `cumulative` or `delta`. Defaults to `cumulative`.
-3. `headers` - Additional headers to send with exported metrics. This can be used for authorization headers. By default, headers are loaded from the config. If that is not set, they can be taken from the environment variables `OTEL_EXPORTER_OTLP_HEADERS` and `OTEL_EXPORTER_OTLP_METRICS_HEADERS`. If a header is set in both the environmental variables, the header in the latter overrides the former.
-4. `resourceAttributes` - https://opentelemetry.io/docs/specs/otel/resource/semantic_conventions/#service[Resource attributes, window=_blank] are used for all metrics published. By default, Micrometer adds the following resource attributes:
+2. `batchSize` - number of `Meter` to include in a single payload sent to the backend. The default is 10,000.
+3. `aggregationTemporality` - https://opentelemetry.io/docs/specs/otel/metrics/data-model/#temporality[Aggregation temporality, window=_blank] determines how the additive quantities are expressed, in relation to time. The supported values are `cumulative` or `delta`. Defaults to `cumulative`.
+4. `headers` - Additional headers to send with exported metrics. This can be used for authorization headers. By default, headers are loaded from the config. If that is not set, they can be taken from the environment variables `OTEL_EXPORTER_OTLP_HEADERS` and `OTEL_EXPORTER_OTLP_METRICS_HEADERS`. If a header is set in both the environmental variables, the header in the latter overrides the former.
+5. `resourceAttributes` - https://opentelemetry.io/docs/specs/otel/resource/semantic_conventions/#service[Resource attributes, window=_blank] are used for all metrics published. By default, Micrometer adds the following resource attributes:
 
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