type metrics struct {
    Counter       em.Counter[int64]         `id:"a_counter"`
    Gauge         em.Gauge[int64]           `id:"a_gauge"`
    UpDownCounter em.UpDownCounter[float64] `id:"a_updowncounter"`
    Histogram em.Histogram[float64]         `id:"a_histogram" buckets:"1.0,2.0,3.0"`
}

// ...
func main() {
    // Setup receives the application identifier and optional attributes.
    // It creates a basic meter provider setup to help you get started quickly.
    // For more advanced configurations (exporters, resources, etc.), 
    // use SetupWithMeter.
    err := em.Setup("my-app", attribute.String("some", "attr"))
    if err != nil {
        // ...  
    }

    // Initialize your metrics.
    m, err :=  em.Init[metrics]()
    if err != nil {
        //...
    }

    // Record your measurements
    i.Counter.Inc(em.Attrs(attribute.String("some", "attr")))

    //  Serve your metrics.
    if err = http.ListenAndServe(":8080", promhttp.Handler()); err != nil {
        panic(err)
    }
}

type Counter[T n64] interface {
    // Add records a change of n to the counter.
    Add(n T, opts ...metric.AddOption)

    // AddCtx records a change of n to the counter.
    AddCtx(ctx context.Context, n T, opts ...metric.AddOption)

    // Inc records a change of 1 to the counter.
    Inc(opts ...metric.AddOption)

    // IncCtx records a change of 1 to the counter.
    IncCtx(ctx context.Context, opts ...metric.AddOption)
}

type UpDownCounter[T n64] interface {
    // Add records a change of n to the counter.
    Add(n T, opts ...metric.AddOption)

    // AddCtx records a change of n to the counter.
    AddCtx(ctx context.Context, n T, opts ...metric.AddOption)

    // Inc records a change of 1 to the counter.
    Inc(opts ...metric.AddOption)

    // IncCtx records a change of 1 to the counter.
    IncCtx(ctx context.Context, opts ...metric.AddOption)

    // Dec records a change of -1 to the counter.
    Dec(opts ...metric.AddOption)

    // DecCtx records a change of -1 to the counter.
    DecCtx(ctx context.Context, opts ...metric.AddOption)
}

type Gauge[T n64] interface {
    // Record records the value of n to the gauge.
    Record(n T, opts ...metric.RecordOption)

    // RecordCtx records the value of n to the gauge.
    RecordCtx(ctx context.Context, n T, opts ...metric.RecordOption)
}

type Histogram[T n64] interface {
    // Record adds a value to the distribution.
    Record(n T, opts ...metric.RecordOption)

    // RecordCtx adds a value to the distribution.
    RecordCtx(ctx context.Context, n T, opts ...metric.RecordOption)

    // Measure creates a starting point using time.Now and returns a function
    // that records the time elapsed since the starting point. The returned
    // function may also receive record options to further support information
    // that may vary along a given procedure.
    Measure(transform timeSub[T], opts ...metric.RecordOption) func(opts ...metric.RecordOption)

    // MeasureCtx creates a starting point using time.Now and returns a function
    // that records the time elapsed since the starting point. The returned
    // function may also receive record options to further support information
    // that may vary along a given procedure.
    MeasureCtx(ctx context.Context, transform timeTransform[T], opts ...metric.RecordOption) func(opts ...metric.RecordOption)
}

type PostgresMetrics struct{
    OpCount em.Counter[int64]    `id:"operations_performed"`
    OpTime  em.Histogram[int64]  `id:"operation_time"`
}

type dbMetrics struct {
    Master struct {
        PostgresMetrics
        WriteCounter em.Counter[int64] `id:"db_write_counter"`
    } `attrs:"sub, master"`

    PostgresMetrics `attrs:"sub, replica"`
}

type Metrics struct {
    DbMetrics dbMetrics `attrs:"sub,postgres"`
}