escapeToSink

private fn

void escapeToSink(Sink)(scope  const(char)[]  s,  ref  Sink sink,  const  char  quote,  const  bool  asciiOnly) if (is(typeof(sink.put("test")))  ||  is(typeof(sink.put('c'))))

@safe

Escape the contents of a UTF-8 string and write to a sink.

This is the core escape logic shared by escapeJSONString and writeJSONString. It handles control characters, quote escaping, and optional ASCII-only output with proper UTF-16 surrogate pair encoding for non-BMP characters.

Malformed UTF-8 sequences are replaced with the Unicode replacement character (U+FFFD).

Parameters

`s`	Input UTF-8 string to escape.
`sink`	Output sink to write escaped content to.
`quote`	Quote character that must be escaped (`'"'` or `'\''`).
`asciiOnly`	When `true`, escape non-ASCII code points using `\uXXXX` sequences.