Add fields for eager workflow dispatch from StartWorkflowExecution (#255)

Co-authored-by: Spencer Judge <[email protected]>

Author: bergundy

temporal/api/workflowservice/v1/request_response.proto

@@ -168,10 +168,19 @@ message StartWorkflowExecutionRequest {
     temporal.api.common.v1.Memo memo = 14;
     temporal.api.common.v1.SearchAttributes search_attributes = 15;
     temporal.api.common.v1.Header header = 16;
+    // Request to get the first workflow task inline in the response bypassing matching service and worker polling.
+    // If set to `true` the caller is expected to have a worker available and capable of processing the task.
+    // The returned task will be marked as started and is expected to be completed by the specified
+    // `workflow_task_timeout`.
+    bool request_eager_execution = 17;
 }
 
 message StartWorkflowExecutionResponse {
     string run_id = 1;
+    // When `request_eager_execution` is set on the `StartWorkflowExecutionRequest`, the server - if supported - will
+    // return the first workflow task to be eagerly executed.
+    // The caller is expected to have a worker available to process the task.
+    PollWorkflowTaskQueueResponse eager_workflow_task = 2;
 }
 
 message GetWorkflowExecutionHistoryRequest {
@@ -851,6 +860,9 @@ message GetSystemInfoResponse {
 
         // True if server supports upserting workflow memo
         bool upsert_memo = 7;
+
+        // True if server supports eager workflow task dispatching for the StartWorkflowExecution API
+        bool eager_workflow_start = 8;
     }
 }