code: def __init__(self, tlwh, score, temp_feat, buffer_size=30):
      # wait activate
      self._tlwh = np.asarray(tlwh, dtype=np.float)
      self.kalman_filter = None
      self.mean, self.covariance = None, None
      self.is_activated = False
  
      self.score = score
      self.tracklet_len = 0
  
      self.smooth_feat = None
      self.update_features(temp_feat)
      self.features = deque([], maxlen=buffer_size)
      self.alpha = 0.9
  
imports: import numpy
  from collections import deque, OrderedDict
  from ..matching import jde_matching
  from ppdet.core.workspace import register, serializable
label_desc: Use image node_id 1 to create a new STrack object from inherited base classes: BaseTrack with example: obj = STrack(tlwh, score, temp_feat, buffer_size)