private static ReadOnlySpan <byte> GetUnescapedString(ReadOnlySpan <byte> utf8Source, int idx)
{
// The escaped name is always longer than the unescaped, so it is safe to use escaped name for the buffer length.
int length = utf8Source.Length;
byte[] pooledName = null;
Span <byte> unescapedName = length <= JsonConstants.StackallocThreshold ?
stackalloc byte[length] :
(pooledName = ArrayPool <byte> .Shared.Rent(length));
JsonReaderHelper.Unescape(utf8Source, unescapedName, idx, out int written);
ReadOnlySpan <byte> propertyName = unescapedName.Slice(0, written).ToArray();
if (pooledName != null)
{
// We clear the array because it is "user data" (although a property name).
new Span <byte>(pooledName, 0, written).Clear();
ArrayPool <byte> .Shared.Return(pooledName);
}
return(propertyName);
}