Merge bitcoin/bitcoin#34483: refactor: Use SpanReader over DataStream

fa0677d131 refactor: Use SpanReader over DataStream (MarcoFalke)
fad3eb3956 refactor: Use SpanReader over DataStream (MarcoFalke)
fa06e26764 refactor: [qt] Use SpanReader to avoid two vector copies (MarcoFalke)
fabd4d2e2e refactor: Avoid UB in SpanReader::ignore (MarcoFalke)
fa20bc2ec2 refactor: Use empty() over eof() in the streams interface (MarcoFalke)
fa879db735 test: Read debug log for self-checking comment (MarcoFalke)

Pull request description:

  This changes all places, where possible, to use SpanReader over DataStream. This makes the code easier to read and reason about, because `SpanReader` can never write data. Also, the code should be minimally faster, because it avoids a full redundant copy of the whole vector of bytes.

ACKs for top commit:
  stickies-v:
    re-ACK fa0677d131
  achow101:
    ACK fa0677d131
  janb84:
    re ACK fa0677d131
  sipa:
    crACK fa0677d131

Tree-SHA512: 1d9f43fc6e71d481cf7b8f8457f479745ee331734649e9e2c2ab00ce5d317112796c77afc328612ed004e65ac5c16fc92279d760cfb012cfddce9098c4af810f

src/net.cpp

@@ -201,8 +201,8 @@ static std::vector<CAddress> ConvertSeeds(const std::vector<uint8_t> &vSeedsIn)
     const auto one_week{7 * 24h};
     std::vector<CAddress> vSeedsOut;
     FastRandomContext rng;
-    ParamsStream s{DataStream{vSeedsIn}, CAddress::V2_NETWORK};
-    while (!s.eof()) {
+    ParamsStream s{SpanReader{vSeedsIn}, CAddress::V2_NETWORK};
+    while (!s.empty()) {
         CService endpoint;
         s >> endpoint;
         CAddress addr{endpoint, SeedsServiceFlags()};