static _addAttributes(shaderBuilder, numTexCoords) {
    for (let i = 0; i < numTexCoords; i++) {
      shaderBuilder.addAttribute("vec2", `a_imagery_texCoord_${i}`);
      shaderBuilder.addVarying("vec2", `v_imagery_texCoord_${i}`);
    }

    const functionId = "initializeImageryAttributes";
    const signature = `void ${functionId}()`;
    shaderBuilder.addFunction(functionId, signature, ShaderDestination.VERTEX);

    for (let i = 0; i < numTexCoords; i++) {
      shaderBuilder.addFunctionLines(functionId, [
        `v_imagery_texCoord_${i} = a_imagery_texCoord_${i};`,
      ]);
    }
  }
Add the attribute- and varying definitions for the imagery texture
coordinates to the given shader.

This includes the definition of the <code>initializeImageryAttributes</code>
function that assigns the attribute values to varyings in the vertex shader.

@param {ShaderBuilder} shaderBuilder The shader builder
@param {number} numTexCoords The number of imagery texture coordinate sets