public static ReadOnlyMemory <char> GetTag <T>(this ReadOnlyMemory <char> fixElement)
        {
            int tagValueSeparatorIndex = fixElement.GetTagValueSeparatorIndex();

            return(fixElement.Slice(0, tagValueSeparatorIndex));
        }
        public static (ReadOnlyMemory <char> tag, ReadOnlyMemory <char> value) GetTagAndValue(this ReadOnlyMemory <char> fixElement)
        {
            int tagValueSeparatorIndex = fixElement.GetTagValueSeparatorIndex();

            return(fixElement.Slice(0, tagValueSeparatorIndex), fixElement.Slice(tagValueSeparatorIndex + 1));
        }