Fragmented text frame treated as invalid if it contains partial utf-8

[airPenetration]

fastwebsockets/src/lib.rs

Lines 647 to 650 in 7d53d01

	}
	OpCode::Text => {
	if frame.fin && !frame.is_utf8() {
	(Err(WebSocketError::InvalidUTF8), None)

A single utf-8 character may contain multiple bytes and fragmentation may lead to the last segment having partial utf-8.

rfc 6455 has already suggested this.

I can guess that this is relatively unlikely to happen, fragmentation of a text segment from the middle of a non ascii character, but is not impossible. Specially if the text contains 4-byte emojis or is a non English text.