aya-log: add `#[must_use]` attribute to `EbpfLogger`

aya-log/src/lib.rs

@@ -95,6 +95,7 @@ unsafe impl Pod for DisplayHintWrapper {}
 /// Log messages generated by `aya_log_ebpf` using the [log] crate.
 ///
 /// For more details see the [module level documentation](crate).
+#[must_use = "The logger needs to be continuously flushed to actually receive log messages in userspace."]
 pub struct EbpfLogger<T> {
     ring_buf: RingBuf<MapData>,
     logger: T,