Add Metadata collection (#1683)

NOTICES.txt

@@ -31,6 +31,16 @@ It also uses derivations of SwiftNIO's lock 'NIOLock.swift' and locked value box
 
 ---
 
+This product uses derivations of SwiftNIOHTTP2's implementation of case
+insensitive comparison of strings, found in 'HPACKHeader.swift'.
+    
+    * LICENSE (Apache License 2.0):
+      * https://github.com/apple/swift-nio-http2/blob/main/LICENSE.txt
+    * HOMEPAGE:
+      * https://github.com/apple/swift-nio-http2
+
+---
+
 This product contains a derivation of the backpressure aware async stream from
 the Swift project.
 
@@ -38,3 +48,12 @@ the Swift project.
     * https://github.com/apple/swift/blob/main/LICENSE.txt
   * HOMEPAGE:
     * https://github.com/apple/swift
+
+---
+
+This product uses derivations of swift-extras/swift-extras-base64 'Base64.swift'.
+
+  * LICENSE (Apache License 2.0):
+    * https://github.com/swift-extras/swift-extras-base64/blob/main/LICENSE
+  * HOMEPAGE:
+    * https://github.com/swift-extras/swift-extras-base64