Improve JSON str encode performance - #459

import random
import string
from time import perf_counter_ns

from orjson import dumps
from msgspec.json import encode

CHARS = string.ascii_letters
CHARS_WITH_ESCAPES = "\x01\n'\"" + string.ascii_letters


def randstr(chars):
    k = random.randint(2, 64)
    return "".join(random.choices(chars, k=k))


N = 1000
M = 10000
random.seed(42)

for header, chars in [("No Escapes:", CHARS), ("With Escapes:", CHARS_WITH_ESCAPES)]:
    print(header)
    data = [randstr(chars) for _ in range(N)]

    start = perf_counter_ns()
    for _ in range(M):
        encode(data)
    stop = perf_counter_ns()
    print(f"- msgspec: {(stop - start) / (1000 * M):.1f} us")

    start = perf_counter_ns()
    for _ in range(M):
        dumps(data)
    stop = perf_counter_ns()
    print(f"- orjson: {(stop - start) / (1000 * M):.1f} us")