public static void serializeTrailersAsMessage(ByteBuf byteBuf, HttpHeaders trailers) {
        for (Map.Entry<AsciiString, String> trailer : trailers) {
            encodeHeader(trailer.getKey(), trailer.getValue(), byteBuf);
        }
    }
Appends the serialized {@link HttpHeaders} into the specifed {@link ByteBuf}.
grpc-protocol/src/main/java/com/linecorp/armeria/internal/common/grpc/protocol/GrpcTrailersUtil.java