Add client side endpoint

common/eth2/src/lib.rs

@@ -2664,6 +2664,22 @@ impl BeaconNodeHttpClient {
         )
         .await
     }
+
+    /// `POST validator/beacon_committee_selections`
+    pub async fn post_validator_beacon_committee_selections(
+        &self,
+        selections: &[BeaconCommitteeSelection],
+    ) -> Result<(), Error> {
+        let mut path = self.eth_path(V1)?;
+
+        path.path_segments_mut()
+            .map_err(|()| Error::InvalidUrl(self.server.clone()))?
+            .push("validator")
+            .push("beacon_committee_selections");
+
+        self.post_with_timeout(path, &selections, self.timeouts.attester_duties)
+            .await
+    }
 }
 
 /// Returns `Ok(response)` if the response is a `200 OK` response. Otherwise, creates an