Jon Hanna
7a93892d03
Skip attempting write when string is empty. FirstCharToEscape was introduced for the async version and gives a faster means to identify the first block before any escaping, so may as well use it here too. Conversely, WriteEscapedStringThroughBuffer was introduced to share code between the sync and async versions, but later optimisations meant it was no longer used by the async. Inline the code back again.
