Merge pull request #58 from Sovietaced/accessToken

Update README for background fetching

README.md

@@ -9,10 +9,11 @@ includes support for telemetry (ie. OpenTelemetry), minimizing verification late
 
 ## Examples
 
-### Access Token Validation
+### Token Validation
 
 ```go 
 package main
+
 import (
     "context"
     verifier "github.com/sovietaced/okta-jwt-verifier"
@@ -29,6 +30,39 @@ func main() {
     accessToken := "..."
     token, err = v.VerifyAccessToken(ctx, accessToken)
 }
+```
+
+### Background Fetching Optimization
+By default, the okta JWT verifier will lazily fetch OIDC metadata and JSON Web Key sets. When the first call to verify a 
+token is made a couple of HTTP requests will be made inline and block your call to verify the token. You can configure 
+the verifier to fetch OIDC metadata and JSON Web Key sets asynchronously in the background to optimize token
+verification duration. 
+
+```go 
+package main
+
+import (
+    "context"
+    kf "github.com/sovietaced/okta-jwt-verifier/keyfunc/okta"
+    md "github.com/sovietaced/okta-jwt-verifier/metadata/okta"
+    verifier "github.com/sovietaced/okta-jwt-verifier"
+)
+
+func main() {
+    ctx := context.Background()
+    issuer := "https://test.okta.com"
+
+    mpProvider, err := md.NewMetadataProvider(issuer, md.WithFetchStrategy(md.Background))
+    kfProvider, err := kf.NewKeyfuncProvider(mpProvider, kf.WithFetchStrategy(kf.Background))
+    v, err := verifier.NewVerifier(issuer, verifier.WithKeyfuncProvider(kfProvider))
+
+    idToken := "..."
+    token, err := v.VerifyIdToken(ctx, idToken)
 
+    accessToken := "..."
+    token, err = v.VerifyAccessToken(ctx, accessToken)
+}
 ```
 
+
+