warning: doc list item without indentation
    --> src/push_service.rs:1731:9
     |
1731 |     /// principle, they will consider any string as "unknown", so other strings may work too.
     |         ^
     |
     = help: if this is supposed to be its own paragraph, add a blank line
     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#doc_lazy_continuation
help: indent this line
     |
1731 |     ///   principle, they will consider any string as "unknown", so other strings may work too.
     |         ++

warning: doc list item without indentation
    --> src/push_service.rs:1730:9
     |
1730 |     /// "android-2021-03" allegedly implies FCM support, whereas the other strings don't.  In
     |         ^
     |
     = help: if this is supposed to be its own paragraph, add a blank line
     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#doc_lazy_continuation
     = note: `#[warn(clippy::doc_lazy_continuation)]` on by default
help: indent this line
     |
1730 |     ///   "android-2021-03" allegedly implies FCM support, whereas the other strings don't.  In
     |         ++

warning: field `certificate` is never read
   --> src/push_service.rs:214:5
    |
212 | struct SenderCertificateJson {
    |        --------------------- field in this struct
213 |     #[serde(with = "serde_base64")]
214 |     certificate: Vec<u8>,
    |     ^^^^^^^^^^^
    |
    = note: `SenderCertificateJson` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysis
    = note: `#[warn(dead_code)]` on by default