private static String simpleConcat(String prefix, String path) {
        try (TemporaryThreadLocals tmp = TemporaryThreadLocals.acquire()) {
            return tmp.stringBuilder()
                      .append(prefix)
                      .append(path)
                      .toString();
        }
    }
Concatenates the specified {@code prefix} and {@code path} into an absolute path.

@throws IllegalArgumentException if {@code prefix} is not an absolute path prefix
core/src/main/java/com/linecorp/armeria/internal/common/ArmeriaHttpUtil.java