remove foundation api usage

Author: t089

Sources/AWSLambdaEvents/Utils/DateWrappers.swift

@@ -83,7 +83,7 @@ public struct RFC5322DateTimeCoding: Decodable, Sendable {
         // RFC5322 dates sometimes have the alphabetic version of the timezone in brackets after the numeric version. The date formatter
         // fails to parse this so we need to remove this before parsing.
         if let bracket = string.firstIndex(of: "(") {
-            string = String(string[string.startIndex..<bracket].trimmingCharacters(in: .whitespaces))
+            string = String(string[string.startIndex..<bracket]._timming(while: { $0.isWhitespace }))
         }
         do {
             self.wrappedValue = try Date(string, strategy: RFC5322DateStrategy())
@@ -109,6 +109,32 @@ public struct RFC5322DateTimeCoding: Decodable, Sendable {
     }*/
 }
 
+extension RangeReplaceableCollection {
+    func _timming(while predicate: (Element) -> Bool) -> SubSequence {
+        var idx = startIndex
+        while idx < endIndex && predicate(self[idx]) {
+            formIndex(after: &idx)
+        }
+
+        let startOfNonTrimmedRange = idx // Points at the first char not in the set
+        guard startOfNonTrimmedRange != endIndex else {
+            return self[endIndex...]
+        }
+
+        let beforeEnd = index(endIndex, offsetBy: -1)
+        guard startOfNonTrimmedRange < beforeEnd else {
+            return self[startOfNonTrimmedRange ..< endIndex]
+        }
+
+        var backIdx = beforeEnd
+        // No need to bound-check because we've already trimmed from the beginning, so we'd definitely break off of this loop before `backIdx` rewinds before `startIndex`
+        while predicate(self[backIdx]) {
+            formIndex(&backIdx, offsetBy: -1)
+        }
+        return self[startOfNonTrimmedRange ... backIdx]
+    }
+}
+
 struct RFC5322DateError: Error {}
 
 struct RFC5322DateStrategy: ParseStrategy {