function configureTextBuilder(config) {
  if (hasRequested) {
    console.warn('configureTextBuilder called after first font request; will be ignored.')
  } else {
    assign(CONFIG, config)
  }
}
Customizes the text builder configuration. This must be called prior to the first font processing
request, and applies to all fonts.

@param {String} config.defaultFontURL - The URL of the default font to use for text processing
                requests, in case none is specified or the specifiede font fails to load or parse.
                Defaults to "Roboto Regular" from Google Fonts.
@param {String} config.unicodeFontsURL - A custom location for the fallback unicode-font-resolver
                data and font files, if you don't want to use the default CDN. See
                https://github.com/lojjic/unicode-font-resolver for details. It can also be
                configured per text instance, but this lets you do it once globally.
@param {Number} config.sdfGlyphSize - The default size of each glyph's SDF (signed distance field)
                texture used for rendering. Must be a power-of-two number, and applies to all fonts,
                but note that this can also be overridden per call to `getTextRenderInfo()`.
                Larger sizes can improve the quality of glyph rendering by increasing the sharpness
                of corners and preventing loss of very thin lines, at the expense of memory. Defaults
                to 64 which is generally a good balance of size and quality.
@param {Number} config.sdfExponent - The exponent used when encoding the SDF values. A higher exponent
                shifts the encoded 8-bit values to achieve higher precision/accuracy at texels nearer
                the glyph's path, with lower precision further away. Defaults to 9.
@param {Number} config.sdfMargin - How much space to reserve in the SDF as margin outside the glyph's
                path, as a percentage of the SDF width. A larger margin increases the quality of
                extruded glyph outlines, but decreases the precision available for the glyph itself.
                Defaults to 1/16th of the glyph size.
@param {Number} config.textureWidth - The width of the SDF texture; must be a power of 2. Defaults to
                2048 which is a safe maximum texture dimension according to the stats at
                https://webglstats.com/webgl/parameter/MAX_TEXTURE_SIZE and should allow for a
                reasonably large number of glyphs (default glyph size of 64^2 and safe texture size of
                2048^2, times 4 channels, allows for 4096 glyphs.) This can be increased if you need to
                increase the glyph size and/or have an extraordinary number of glyphs.
@param {Boolean} config.useWorker - Whether to run typesetting in a web worker. Defaults to true.