Hand

属性：

• [arm]
• [basis]
• [confidence]
• [direction]
• [fingers]
• [frame]
• [grab_strength]
• [id]
• [is_left]
• [is_right]
• [is_valid]
• [palm_normal]
• [palm_position]
• [palm_velocity]
• [palm_width]
• [pinch_strength]
• [pointables]
• [sphere_center]
• [sphere_radius]
• [stabilized_palm_position]
• [time_visible]
• [tools]
• [wrist_position]