feat: add websocket upstream adapter

crates/crank-adapter-websocket/src/lib.rs

@@ -0,0 +1,35 @@
+mod client;
+mod error;
+mod session;
+
+use std::collections::BTreeMap;
+
+use serde::{Deserialize, Serialize};
+use serde_json::Value;
+
+pub use client::WebsocketAdapter;
+pub use error::WebsocketAdapterError;
+pub use session::{HeartbeatPolicy, ReconnectPolicy};
+
+#[derive(Clone, Debug, PartialEq, Serialize, Deserialize, Default)]
+pub struct WebsocketWindowRequest {
+    #[serde(default, skip_serializing_if = "BTreeMap::is_empty")]
+    pub headers: BTreeMap<String, String>,
+    pub window_duration_ms: u64,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub max_items: Option<u32>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub heartbeat_interval_ms: Option<u64>,
+    #[serde(default)]
+    pub reconnect_max_attempts: u32,
+    #[serde(default)]
+    pub reconnect_backoff_ms: u64,
+}
+
+#[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
+pub struct WebsocketWindowResponse {
+    pub status_code: u16,
+    #[serde(default, skip_serializing_if = "BTreeMap::is_empty")]
+    pub headers: BTreeMap<String, String>,
+    pub body: Value,
+}