UTF8Decoder.decode

auto decoder = UTF8Decoder("Eng 日本語 Кир ©€");
import std.algorithm: equal;
assert(equal(decoder.decode(), "Eng 日本語 Кир ©€"d));

auto range = decoder.decode();
auto saved = range.save;

range.popFront();
range.popFront();
range.popFront();
range.popFront();
range.popFront();

assert(equal(range, "本語 Кир ©€"d));
assert(equal(saved, "Eng 日本語 Кир ©€"d));