try locking reader while processing results.

derby/derby.go

@@ -219,6 +219,7 @@ func (dc *DerbyClock) readLoop() {
 			if b[0] == ' ' {
 				// These characters could indicate a complete result or a separator
 				// Try to extract a result from the buffer
+				dc.mu.Lock()
 				result := dc.tryExtractResult(buffer)
 				if result != nil {
 					// Send lane finish event
@@ -229,6 +230,7 @@ func (dc *DerbyClock) readLoop() {
 				}
 				// Clear the buffer after a result is extracted
 				buffer = buffer[:0]
+				dc.mu.Unlock()
 			}
 
 		}