Added a span feature which enables storing spans in events

Author: Mingun

.github/workflows/rust.yml

@@ -63,6 +63,10 @@ jobs:
       env:
         LLVM_PROFILE_FILE: coverage/serialize-escape-html-%p-%m.profraw
       run: cargo test --features serialize,escape-html
+    - name: Run tests (serialize+span)
+      env:
+        LLVM_PROFILE_FILE: coverage/serialize-span-%p-%m.profraw
+      run: cargo test --features serialize,span
     - name: Run tests (all features)
       env:
         LLVM_PROFILE_FILE: coverage/all-features-%p-%m.profraw

Cargo.toml

@@ -180,6 +180,10 @@ serde-types = ["serde/derive"]
 ## If you need that, use the `serde-types` feature.
 serialize = ["serde"] # "dep:" prefix only avalible from Rust 1.60
 
+## Enables gathering spans in events, which can slowdown parser a bit and increase
+## memory consumption for events
+span = []
+
 [package.metadata.docs.rs]
 # document all features
 all-features = true