Prefer reparsing to prepending byte

I must've missed the point of this section before, oops. I'd prefer not
to have the `start` var, but it's necessary because I can't subtract a
number from the iterator right now:

zeek/spicy#1920

analyzer/resp.spicy

@@ -18,20 +18,23 @@ public type ServerMessages = unit {
 
 public type ClientData = unit {
     %synchronize-after = b"\x0d\x0a";
+
+    on %init() { self.start = self.input(); }
+
     # Clients can only be an array or inline
-    ty: uint8 &convert=DataType($$);
+    ty: uint8 &convert=DataType($$) {
+        if (self.ty != DataType::ARRAY) {
+            # This is inline, so we need to reparse `ty`
+            self.set_input(self.start);
+        }
+    }
     if (self.ty == DataType::ARRAY) {
         multibulk: Array;
     } else {
-        # HACK: If the type isn'tan array, this is just some random unserialized
-        # string until \r\n - do this by prepending the type to the remaining bytes.
-        # Formally in Redis code, that's an "inline command."
-        #
-        # As an extra point, this is handled in redis in `processInlineBuffer`,
-        # which has a hardcoded limit of 1024*64. That seems too big. We'll do 1024.
-        inline: RedisBytes &convert=(pack(cast<uint8>(self.ty), spicy::ByteOrder::Network) + $$) &max-size=1024;
+        inline: RedisBytes &max-size=1024;
     };
 
+    var start: iterator<stream>;
     var command: Redis::Command;
 
     on %done {