separate signer.

fix ilm feature.

crates/signer/src/constants.rs

@@ -0,0 +1,10 @@
+use time::{format_description::FormatItem, macros::format_description};
+
+pub const UNSIGNED_PAYLOAD: &str = "UNSIGNED-PAYLOAD";
+pub const UNSIGNED_PAYLOAD_TRAILER: &str = "STREAMING-UNSIGNED-PAYLOAD-TRAILER";
+
+pub const TOTAL_WORKERS: i64 = 4;
+
+pub const SIGN_V4_ALGORITHM: &str = "AWS4-HMAC-SHA256";
+pub const ISO8601_DATEFORMAT: &[FormatItem<'_>] =
+    format_description!("[year]-[month]-[day]T[hour]:[minute]:[second].[subsecond]Z");