Partially implement receiving pipeline

SessionMessagingKit/Pipelines/ReceivingPipeline.swift

@@ -1,8 +1,22 @@
+import SessionUtilities
 
 public enum ReceivingPipeline {
 
-    // 1. Decrypt
-    // 2. Convert binary to proto
-    // 3. Convert proto to message
-    // 4. Handle message
+    public static func parse(_ data: Data) -> Message? {
+        // TODO: Decrypt
+        let proto: SNProtoContent
+        do {
+            proto = try SNProtoContent.parseData(data)
+        } catch {
+            SNLog("Couldn't parse proto due to error: \(error).")
+            return nil
+        }
+        if let readReceipt = ReadReceipt.fromProto(proto) { return readReceipt }
+        if let sessionRequest = SessionRequest.fromProto(proto) { return sessionRequest }
+        if let typingIndicator = TypingIndicator.fromProto(proto) { return typingIndicator }
+        if let closedGroupUpdate = ClosedGroupUpdate.fromProto(proto) { return closedGroupUpdate }
+        if let expirationTimerUpdate = ExpirationTimerUpdate.fromProto(proto) { return expirationTimerUpdate }
+        if let visibleMessage = VisibleMessage.fromProto(proto) { return visibleMessage }
+        return nil
+    }
 }

SessionMessagingKit/Utilities/FixedWidthInteger+BigEndian.swift

@@ -1,5 +1,4 @@
 
-
 internal extension FixedWidthInteger {
 
     init?(fromBigEndianBytes bytes: [UInt8]) {