Feature flag lookup for prometheus_metrics_method_instrumentation gets called repeatedly

I see this repeatedly in my dev environment logs:

  Feature::FlipperGate Load (2.4ms)  SELECT "feature_gates".* FROM "feature_gates" WHERE "feature_gates"."feature_key" = $1  [["feature_key", "prometheus_metrics_method_instrumentation"]]
  Feature::FlipperGate Load (1.0ms)  SELECT "feature_gates".* FROM "feature_gates" WHERE "feature_gates"."feature_key" = $1  [["feature_key", "prometheus_metrics_method_instrumentation"]]
  Feature::FlipperGate Load (1.5ms)  SELECT "feature_gates".* FROM "feature_gates" WHERE "feature_gates"."feature_key" = $1  [["feature_key", "prometheus_metrics_method_instrumentation"]]
  Feature::FlipperGate Load (1.4ms)  SELECT "feature_gates".* FROM "feature_gates" WHERE "feature_gates"."feature_key" = $1  [["feature_key", "prometheus_metrics_method_instrumentation"]]
  Feature::FlipperGate Load (0.2ms)  SELECT "feature_gates".* FROM "feature_gates" WHERE "feature_gates"."feature_key" = $1  [["feature_key", "prometheus_metrics_method_instrumentation"]]
  Feature::FlipperGate Load (1.3ms)  SELECT "feature_gates".* FROM "feature_gates" WHERE "feature_gates"."feature_key" = $1  [["feature_key", "prometheus_metrics_method_instrumentation"]]
  Feature::FlipperGate Load (1.5ms)  SELECT "feature_gates".* FROM "feature_gates" WHERE "feature_gates"."feature_key" = $1  [["feature_key", "prometheus_metrics_method_instrumentation"]]
  Feature::FlipperGate Load (0.4ms)  SELECT "feature_gates".* FROM "feature_gates" WHERE "feature_gates"."feature_key" = $1  [["feature_key", "prometheus_metrics_method_instrumentation"]]
  Feature::FlipperGate Load (0.2ms)  SELECT "feature_gates".* FROM "feature_gates" WHERE "feature_gates"."feature_key" = $1  [["feature_key", "prometheus_metrics_method_instrumentation"]]
  Feature::FlipperGate Load (0.2ms)  SELECT "feature_gates".* FROM "feature_gates" WHERE "feature_gates"."feature_key" = $1  [["feature_key", "prometheus_metrics_method_instrumentation"]]
  Feature::FlipperGate Load (0.3ms)  SELECT "feature_gates".* FROM "feature_gates" WHERE "feature_gates"."feature_key" = $1  [["feature_key", "prometheus_metrics_method_instrumentation"]]
  Feature::FlipperGate Load (0.2ms)  SELECT "feature_gates".* FROM "feature_gates" WHERE "feature_gates"."feature_key" = $1  [["feature_key", "prometheus_metrics_method_instrumentation"]]
  Feature::FlipperGate Load (0.2ms)  SELECT "feature_gates".* FROM "feature_gates" WHERE "feature_gates"."feature_key" = $1  [["feature_key", "prometheus_metrics_method_instrumentation"]]
  Feature::FlipperGate Load (1.4ms)  SELECT "feature_gates".* FROM "feature_gates" WHERE "feature_gates"."feature_key" = $1  [["feature_key", "prometheus_metrics_method_instrumentation"]]
  Feature::FlipperGate Load (0.2ms)  SELECT "feature_gates".* FROM "feature_gates" WHERE "feature_gates"."feature_key" = $1  [["feature_key", "prometheus_metrics_method_instrumentation"]]
  Feature::FlipperGate Load (1.4ms)  SELECT "feature_gates".* FROM "feature_gates" WHERE "feature_gates"."feature_key" = $1  [["feature_key", "prometheus_metrics_method_instrumentation"]]
  Feature::FlipperGate Load (0.3ms)  SELECT "feature_gates".* FROM "feature_gates" WHERE "feature_gates"."feature_key" = $1  [["feature_key", "prometheus_metrics_method_instrumentation"]]
  Feature::FlipperGate Load (1.3ms)  SELECT "feature_gates".* FROM "feature_gates" WHERE "feature_gates"."feature_key" = $1  [["feature_key", "prometheus_metrics_method_instrumentation"]]
  Feature::FlipperGate Load (0.3ms)  SELECT "feature_gates".* FROM "feature_gates" WHERE "feature_gates"."feature_key" = $1  [["feature_key", "prometheus_metrics_method_instrumentation"]]
  Feature::FlipperGate Load (1.1ms)  SELECT "feature_gates".* FROM "feature_gates" WHERE "feature_gates"."feature_key" = $1  [["feature_key", "prometheus_metrics_method_instrumentation"]]
  Feature::FlipperGate Load (1.4ms)  SELECT "feature_gates".* FROM "feature_gates" WHERE "feature_gates"."feature_key" = $1  [["feature_key", "prometheus_metrics_method_instrumentation"]]
  Feature::FlipperGate Load (0.3ms)  SELECT "feature_gates".* FROM "feature_gates" WHERE "feature_gates"."feature_key" = $1  [["feature_key", "prometheus_metrics_method_instrumentation"]]
  Feature::FlipperGate Load (0.2ms)  SELECT "feature_gates".* FROM "feature_gates" WHERE "feature_gates"."feature_key" = $1  [["feature_key", "prometheus_metrics_method_instrumentation"]]
  Feature::FlipperGate Load (0.9ms)  SELECT "feature_gates".* FROM "feature_gates" WHERE "feature_gates"."feature_key" = $1  [["feature_key", "prometheus_metrics_method_instrumentation"]]
  Feature::FlipperGate Load (3.0ms)  SELECT "feature_gates".* FROM "feature_gates" WHERE "feature_gates"."feature_key" = $1  [["feature_key", "prometheus_metrics_method_instrumentation"]]
  Feature::FlipperGate Load (0.2ms)  SELECT "feature_gates".* FROM "feature_gates" WHERE "feature_gates"."feature_key" = $1  [["feature_key", "prometheus_metrics_method_instrumentation"]]
  Feature::FlipperGate Load (1.4ms)  SELECT "feature_gates".* FROM "feature_gates" WHERE "feature_gates"."feature_key" = $1  [["feature_key", "prometheus_metrics_method_instrumentation"]]
  Feature::FlipperGate Load (1.4ms)  SELECT "feature_gates".* FROM "feature_gates" WHERE "feature_gates"."feature_key" = $1  [["feature_key", "prometheus_metrics_method_instrumentation"]]
  Feature::FlipperGate Load (0.6ms)  SELECT "feature_gates".* FROM "feature_gates" WHERE "feature_gates"."feature_key" = $1  [["feature_key", "prometheus_metrics_method_instrumentation"]]

What's surprising here is that Flipper has a memoization middleware that we normally use in a non-test environment: https://github.com/jnunemaker/flipper/blob/master/docs/Optimization.md

I think this is only in 10.3 based on 46cd2d93, so we should investigate ASAP.

/cc: @pchojnacki, @joshlambert, @bjk-gitlab