Adding N annotations takes O(N^2) time

Plotly is unreasonably slow to add more than a few hundred annotations to a plot. This code

import time

import plotly


fig = plotly.graph_objects.Figure()

NUM_ANNOTATIONS=1000

start_time = time.monotonic()
for i in range(NUM_ANNOTATIONS):
    fig.add_annotation(
        x=i,
        y=time.monotonic() - start_time,
        text=str(i),
    )
    print(i)
fig.update_layout(
    xaxis_range=[0,NUM_ANNOTATIONS],
    yaxis_range=[0,time.monotonic() - start_time],
    xaxis_title_text="# Annotations",
    yaxis_title_text="Cumulative Time [s]",
)
fig.show()

produces this plot

首先运行 issue 中的复现脚本，并对重复调用 fig.add_annotation 进行性能分析。跟踪 Python Figure 的注释路径，以确定累积成本增长的位置，然后使用同一个脚本验证添加大量注释不再表现出二次行为。