code: function tr_init() {
  
  			l_desc.dyn_tree = dyn_ltree;
  			l_desc.stat_desc = StaticTree.static_l_desc;
  
  			d_desc.dyn_tree = dyn_dtree;
  			d_desc.stat_desc = StaticTree.static_d_desc;
  
  			bl_desc.dyn_tree = bl_tree;
  			bl_desc.stat_desc = StaticTree.static_bl_desc;
  
  			bi_buf = 0;
  			bi_valid = 0;
  			last_eob_len = 8; // enough lookahead for inflate
  
  			// Initialize the first block of the first file:
  			init_block();
  		}
docs: Initialize the tree data structures for a new zlib stream.