use crate::config::OtelExporter;use crate::metrics::Result;use crate::metrics::validation::validate_tag_key;use crate::metrics::validation::validate_tag_value;use opentelemetry_sdk::metrics::InMemoryMetricExporter;use std::collections::BTreeMap;use std::time::Duration;#[derive(Clone, Debug)]pub enum MetricsExporter {    Otlp(OtelExporter),    InMemory(InMemoryMetricExporter),}#[derive(Clone, Debug)]pub struct MetricsConfig {    pub(crate) environment: String,    pub(crate) service_name: String,    pub(crate) service_version: String,    pub(crate) exporter: MetricsExporter,    pub(crate) export_interval: Option<Duration>,    pub(crate) runtime_reader: bool,    pub(crate) default_tags: BTreeMap<String, String>,}impl MetricsConfig {    pub fn otlp(        environment: impl Into<String>,        service_name: impl Into<String>,        service_version: impl Into<String>,        exporter: OtelExporter,    ) -> Self {        Self {            environment: environment.into(),            service_name: service_name.into(),            service_version: service_version.into(),            exporter: MetricsExporter::Otlp(exporter),            export_interval: None,            runtime_reader: false,            default_tags: BTreeMap::new(),        }    }    /// Create an in-memory config (used in tests).    pub fn in_memory(        environment: impl Into<String>,        service_name: impl Into<String>,        service_version: impl Into<String>,        exporter: InMemoryMetricExporter,    ) -> Self {        Self {            environment: environment.into(),            service_name: service_name.into(),            service_version: service_version.into(),            exporter: MetricsExporter::InMemory(exporter),            export_interval: None,            runtime_reader: false,            default_tags: BTreeMap::new(),        }    }    /// Override the interval between periodic metric exports.    pub fn with_export_interval(mut self, interval: Duration) -> Self {        self.export_interval = Some(interval);        self    }    /// Enable a manual reader for on-demand runtime snapshots.    pub fn with_runtime_reader(mut self) -> Self {        self.runtime_reader = true;        self    }    /// Add a default tag that will be sent with every metric.    pub fn with_tag(mut self, key: impl Into<String>, value: impl Into<String>) -> Result<Self> {        let key = key.into();        let value = value.into();        validate_tag_key(&key)?;        validate_tag_value(&value)?;        self.default_tags.insert(key, value);        Ok(self)    }}